Grammar from First Principles

Everything the SAT tests about English conventions — derived, not memorized.

You said you get the high-level stuff but not the basics. That's normal and it's fixable, because the "basics" are usually taught as a pile of disconnected rules to memorize. They aren't. There are about four underlying ideas, and every rule on the SAT is a consequence of one of them. This guide builds those four ideas first, then derives the rules.

0 · Why grammar has rules at all

Start from the actual engineering problem. Meaning is a structure. Speech is a line.

What you want to communicate is a web of relationships: this thing did that action to that other thing, at this time, and by the way this thing is the one wearing the hat. That's a shape with branches. But you can only say one word at a time, in one order. So you have to flatten the shape into a line, and the listener has to rebuild the shape from the line.

Grammar is the set of conventions that makes that rebuild possible. That's it. That's the whole thing.

And there are only really three tools any language has for signalling structure in a line:

The three signalling tools

Order — put related things next to each other, and put them in a fixed sequence. The dog bit the man ≠ The man bit the dog. English leans on this heavily.
Agreement — make two words change shape to match, so you can tell they belong together even from far apart. The dog runs vs. The dogs run.
Marking — insert little words and symbols whose only job is to label a relationship: of, to, with, that, because, and all punctuation.

Now here is the payoff. Every single SAT grammar question is testing one of those three tools:

Tool	When it breaks, you get…	SAT question types
Agreement	a link to the wrong thing	subject–verb agreement, pronoun–antecedent agreement, verb tense consistency
Order	a modifier attached to the wrong noun	dangling & misplaced modifiers, subject–modifier placement, parallelism
Marking	a boundary you can't find	commas, semicolons, colons, dashes, apostrophes, transitions, prepositions

So you don't have 40 rules to learn. You have three mechanisms, and the "rules" are just what each mechanism looks like in a specific situation. When you can't remember a rule, ask instead: what would a reader be unable to reconstruct here? That question answers almost every SAT grammar item on its own.

A word about "correct"

Grammar rules are conventions, not laws of physics. "Ain't" isn't broken — it's a different convention. The SAT tests one specific convention: formal written Standard American English. So throughout this guide, "wrong" means "wrong on the SAT," not "bad English." Some things you say every day (and that are perfectly fine in speech) are marked wrong here. That's a feature of the test, not a judgment about you.

How to use this

Read Part I properly, once, slowly. It's short. Everything else depends on it. If you only understand one thing, make it §4 Finiteness — it silently controls about half the punctuation questions on the test.
Everything after Part I is lookup. Skip around. Each section is self-contained.
Green ✓ / red ✗ boxes are examples. Colour coding: subject, verb, modifier.
The practice bank at the end has 32 questions with click-to-reveal reasoning. Do them after reading, and force yourself to name the rule before you look.

Part I · Foundations

1. The atom of language: predication

Forget "a sentence is a complete thought." That definition is useless because you can't test it. Here is a definition you can test.

Definition

A predication is: point at something, then assert something about it.

The thing you point at is the subject. What you assert about it is the predicate. The predicate always contains a verb.

Water boils. Point at water. Assert: it boils.

The old copper kettle on the back burner was whistling furiously. Same two parts. Everything else is padding hung off them.

That's the atom. A sentence is one or more predications, glued together legally. Everything else — every adjective, every prepositional phrase, every clause — is decoration attached to one of those two parts.

This gives you your first and most powerful move:

Move #1 — Find the predication

For any sentence on the SAT, ask two questions in this order:

What is the verb? (What is being asserted — an action or a state?)
Who or what is doing / being it? (That's your subject.)

Find the verb first. Subjects are easy to misidentify; verbs are not. Then the subject is whatever answers "who verbs?"

Try it on a deliberately awful sentence:

Buried beneath three feet of volcanic ash for nineteen centuries, the frescoes in the villa's dining room retain their original color.

Verb: retain. Who retains? Not "ash," not "centuries," not "the villa," not "the dining room" — the frescoes retain. Subject = frescoes (plural), so retain (plural verb) is right. Everything before the comma is decoration; everything between "frescoes" and "retain" is decoration. Two words carry the sentence.

2. Word classes are jobs, not identities

The single biggest reason "parts of speech" feel arbitrary is that they're taught as labels stuck to words. They're not. They're jobs a word is doing in a particular sentence. The same word takes different jobs on different days.

I will run tomorrow. "run" is a verb — it's the assertion.

The run was exhausting. Same word, now a noun — it's the thing pointed at.

We compared the two run times. Same word again, now modifying a noun — adjective work.

So learn the jobs, not the lists.

Job	What it does	The test for it
Noun	Names a thing you can point at (concrete or abstract)	Can you put the in front? the dog, the freedom, the arrival
Verb	Asserts an action or a state	Can you change its time? runs / ran / will run
Adjective	Narrows a noun	Fits in "the ___ thing" or "the thing is ___"
Adverb	Narrows a verb, an adjective, another adverb, or a whole clause	Answers how / when / where / to what degree
Preposition	States a relation between a noun and the rest	Fits "the cat ___ the box": in, on, under, near, beside
Conjunction	Glue. Joins two things of the same kind (or hooks a small one onto a big one)	and, but, or / because, although, when
Pronoun	A placeholder pointing back at a noun already mentioned	he, it, they, which, who, this
Determiner	Specifies which or how many of a noun	the, a, this, my, some, three, every

Why the SAT cares about only three of these

Nouns, verbs, and pronouns carry agreement. That's why they're tested constantly. Adjectives and adverbs in English don't change shape to match anything, so they're barely tested. Prepositions and conjunctions are pure marking, so they show up in idiom and transition questions. Determiners are almost never tested.

The four kinds of verb you must be able to tell apart

This distinction quietly drives a lot of questions, so it's worth 60 seconds.

Action verbs — run, decide, corrode. Something happens.
Linking verbs — be, seem, become, appear, remain, and sense verbs (look, sound, taste, feel, smell) when they aren't actions. These don't describe an action; they run an equals sign. The soup is salty means soup = salty. This is why the formal choice is "I feel bad" — an adjective describing you, not an adverb describing how skillfully you perform the act of feeling. (Feel badly is common and defended by some dictionaries; the SAT wants the adjective.)
Auxiliary (helping) verbs — be, have, do plus modals (can, will, should, might, must). These carry the tense and the agreement so the main verb doesn't have to. She has been running. The has does all the grammatical work.
Non-finite verb forms — to walk, walking, walked, written. These look like verbs but cannot anchor a sentence. This is §4 and it is the most important idea in the guide.

3. Phrase vs. clause — the distinction everything hangs on

Definitions

Phrase = a group of words acting as a single unit, with no subject–verb predication inside it.
Clause = a group of words that does contain a subject and a finite verb — i.e. contains a predication.

Phrases are always decoration or a slot-filler. Clauses are structural. Here's the same content packaged both ways:

Phrase: after the storm no verb. Just a labelled chunk of time.

Clause: after the storm passed "storm passed" — subject + verb. This is a predication.

The phrase types you'll actually meet

Prepositional phrase — preposition + noun: in the drawer, of the committee, despite heavy rain. These are the #1 source of subject–verb agreement traps, because the subject of a sentence is never inside a prepositional phrase. Ever. Memorize that.
Participial phrase — starts with an -ing or -ed verb form: running late, exhausted by the climb. Acts as an adjective, so it must sit next to the noun it describes. Source of every dangling-modifier question.
Infinitive phrase — to + verb: to finish the report. Can act as noun, adjective, or adverb.
Appositive phrase — a noun renaming a noun: Marie Curie, a physicist and chemist, won two Nobel Prizes. Almost always fenced by commas (see §18).
Gerund phrase — -ing form used as a noun: Swimming in cold water lowers your heart rate. The whole phrase is the subject and it's singular.

The two kinds of clause

	Independent clause	Dependent (subordinate) clause
Has subject + finite verb?	Yes	Yes
Can stand alone as a sentence?	Yes	No
Why not?	—	A subordinator at the front "downgrades" it into a part of another sentence
Example	the ice melted	because the ice melted

What downgrades a clause

Subordinating conjunctions: after, although, as, as if, because, before, even though, if, in order that, once, since, so that, than, that, though, unless, until, when, whenever, where, whereas, wherever, while.

Relative pronouns: who, whom, whose, which, that — plus the relative adverbs where and when, which subordinate a clause the same way.

Put any of these in front of a perfectly good sentence and it stops being able to stand alone. The ice melted. → Because the ice melted… (and now you're waiting for the rest).

The classic confusion: "however" is not a conjunction

Words like however, therefore, moreover, consequently, nevertheless, furthermore, indeed, instead, thus, in fact, for example are conjunctive adverbs — they signal a logical relation but they have zero grammatical joining power. They cannot hold two independent clauses together with just a comma.

The trail was icy, however we continued.

The trail was icy, therefore, we turned back.

The trail was icy; however, we continued.

The trail was icy. However, we continued.

The trail was icy, but we continued. "but" IS a real conjunction, so comma + but works.

Test it: can the word move around inside its own clause? "We, however, continued." works. "We, but, continued" doesn't. If it can float, it's an adverb, and it can't join clauses.

4. Finiteness — the single most useful idea on this page

Read this section twice. It silently decides half the punctuation questions on the SAT and almost every fragment question.

Definition

A verb form is finite if it is anchored in time and to a subject — that is, it carries tense and shows agreement.
A verb form is non-finite if it doesn't. Non-finite forms are: the infinitive (to walk), the present participle / gerund (walking), and the past participle (walked / written / sung) when used alone.

Only a finite verb can anchor a clause. No finite verb → no clause → no sentence.

Here's the test. Try to put yesterday vs. tomorrow on it, or swap he for they:

writes → he writes / they write / he wrote changes with subject and time. FINITE.

writing → he writing / they writing / *wroting doesn't change. NON-FINITE.

to write → he to write / they to write frozen. NON-FINITE.

is writing → he is writing / they are writing the helper "is/are" carries the finiteness. FINITE (as a unit).

Now watch what this explains.

It explains fragments

The engineers, having reviewed every seal on the booster rocket. "having reviewed" is non-finite. There is NO finite verb. This is a noun with decoration, not a sentence.

The engineers had reviewed every seal on the booster rocket.

The engineers, having reviewed every seal, approved the launch.

It explains why some -ing words start clauses and some don't

Sea levels rising steadily along the eastern seaboard. "rising" is non-finite, so there is no clause here at all — just a noun with decoration. Fragment.

Sea levels are rising steadily along the eastern seaboard.

Sea levels rising, coastal cities are building barriers. Fine — the opening phrase is decoration, and the main clause has a finite verb ("are building").

It gives you a counting rule that solves punctuation mechanically

Move #2 — Count the finite verbs

Number of independent clauses = number of subject + finite-verb pairs not already claimed by a subordinator. (Careful: two verbs sharing one subject — the kettle boiled and whistled — are a compound predicate, i.e. still one clause. That is exactly why you don't put a comma before that and.)
If you have N independent clauses in one sentence, you need N − 1 legal joiners between them.

Legal joiners between two independent clauses (this list is complete):

Period .
Semicolon ;
Comma + FANBOYS , and / , but / , or / , nor / , for / , yet / , so
Colon : (only if clause 2 explains or delivers clause 1)
Dash — (only if clause 2 amplifies or reverses clause 1)
Turn one of them into a dependent clause by adding a subordinator

Anything else — a bare comma, a bare "however," nothing at all — is a run-on, and the SAT will offer it as a wrong answer roughly forever.

5. The technique: strip to the core

Almost every hard SAT sentence is a short simple sentence buried under decoration. The decoration exists to make you agree with the wrong word. So strip it.

Move #3 — Delete-and-check

Mentally cross out, in this order:

Everything between commas / dashes / parentheses (appositives & nonrestrictive clauses)
Every prepositional phrase (of…, in…, with…, along with…, as well as…, including…, among…)
Every participial phrase (-ing…, -ed…)
Every relative clause (who…, which…, that…)

What survives is the skeleton. Check the skeleton. Then put the decoration back and check that each piece is attached to the right thing.

Worked example:

Original: The collection of rare seventeenth-century manuscripts, which the library acquired at auction and which scholars from across Europe now consult regularly, is housed in a climate-controlled vault. Strip the relative clauses: The collection of rare seventeenth-century manuscripts is housed in a vault. Strip the prepositional phrases: The collection is housed. Skeleton: collection (singular) → is (singular). Correct. Trap: "manuscripts" and "scholars" are plural and sit right next to the verb.

Notice that the trap words were placed immediately before the verb. That's not an accident; that's the test doing its job. Your defense is mechanical stripping, not intuition — because your intuition was built by listening to speech, and speech agrees with whatever noun it heard last.

Why your ear is unreliable here (and where it IS reliable)

Unreliable: agreement across distance, who/whom, pronoun case, "than I/me", restrictive commas. Speech routinely violates all of these and nobody notices.
Reliable: idiom and preposition choice (interested in, not interested on), and word order. For those, if it sounds wrong to a fluent speaker, it is wrong. So: use your ear for word choice, use rules for word structure.

Part II · Agreement

6. Subject–verb agreement, derived

The principle: agreement is a rope tying the verb back to its subject across whatever distance separates them. English has almost no agreement left — it survives in exactly one place: present-tense verbs, third person, singular vs. plural. That's why it's so easy to get wrong, and why the SAT tests it constantly.

The whole system

	Singular subject	Plural subject
Present tense	verb takes -s: the dog runs	verb takes no -s: the dogs run
"to be"	is / was	are / were
"to have"	has	have
"to do"	does	do
Past tense (all other verbs)	no agreement at all — the dog ran / the dogs ran

The inverted -s

Here's the thing that trips everyone: for nouns, -s means plural. For verbs, -s means singular. They're opposites. The dogs bark / The dog barks. Exactly one -s per pair. If you see two -s's or zero, look harder.

7. The nine traps — and why each one works

Trap 1 · Interrupting prepositional phrase

Why it works: the last noun you heard becomes the loudest in your head.
The rule it violates: a subject can never be inside a prepositional phrase.

The box of chocolates were left on the counter.

The box of chocolates was left on the counter. box was. "of chocolates" is decoration.

Trap 2 · "Along with," "as well as," "including," "in addition to"

Why it works: these mean "and," so they feel like they should add up. Grammatically they're prepositions, not conjunctions — they don't join subjects, they hang phrases off one.

The senator, along with three aides, were present.

The senator, along with three aides, was present.

The senator and three aides were present. "and" is a real conjunction — now it's genuinely plural.

Trap 3 · Inverted order (verb before subject)

Why it works: your default parser assumes the first noun is the subject. Triggers: sentences starting with There / Here, questions, and sentences opening with a prepositional phrase or negative for emphasis.

There is several reasons for the delay.

There are several reasons for the delay. "There" is a placeholder, never the subject. Flip it: "Several reasons are…"

Among the artefacts was a bronze mirror. Flip it: "A bronze mirror was among the artefacts."

Beneath the floorboards lie the original joists.

Technique: when you see inversion, physically rewrite the sentence in normal order in your head. The error becomes obvious instantly.

Trap 4 · Indefinite pronouns

Why it works: words like each and everyone refer to many people but are grammatically singular. English is being weird; you just have to know the list.

Always SINGULAR	Always PLURAL	Depends on the "of" phrase
each, every, either, neither, one, another, anyone, anybody, anything, everyone, everybody, everything, someone, somebody, something, no one, nobody, nothing, much, little	both, few, several, many, others	some, any, none, all, most, more, half / fractions / percentages, "a lot of"

Each of the twelve jurors has a copy. Each = singular. "of the jurors" is decoration.

Neither of the proposals addresses the cost.

Some of the water is contaminated. water = uncountable → singular

Some of the samples are contaminated. samples = countable plural → plural

That last pair is the whole logic of the third column: for some/any/none/all/most/half, the verb agrees with the noun in the of-phrase, because those words mean "a portion," and a portion takes the number of the stuff it's a portion of. This is the one place where you do look inside the prepositional phrase — and it's an exception you can derive, not memorize.

Trap 5 · Collective nouns

team, committee, jury, family, group, staff, class, audience, government, company, herd, majority.

The principle: a collective noun is singular when the group acts as one body, plural when the members act individually. In American usage (which the SAT follows), treat it as singular by default.

The committee has issued its report. acting as one unit

The committee members have gone home. "members" is a real plural noun — that's the safe fix

The SAT rarely tests the ambiguous case; if it does, the pronoun elsewhere in the sentence tells you which reading is intended. Match them.

Trap 6 · Compound subjects with "or" / "nor" / "either…or" / "neither…nor"

The principle: and adds things together (→ plural). or presents alternatives — only one is actually true at a time — so the verb agrees with the nearer subject.

The director or the producers are going to sign off. nearer = producers → plural

The producers or the director is going to sign off. nearer = director → singular

Neither the students nor the teacher was aware of the change.

Trap 7 · Gerund and clause subjects

The principle: an activity or an idea is one thing, no matter how many plural nouns are inside it.

Restoring the frescoes requires years of work.

What the researchers discovered was unsettling.

Reading old letters is her favorite hobby.

Trap 8 · "One of the ___ who/that…"

This is the hardest one on the test, and it's pure logic once you see it.

She is one of those engineers who insist on triple-checking. Who insists? The ENGINEERS do — she's one of that group. → plural

She is the only one of the engineers who insists on triple-checking. "the only one" — now the group has one member. → singular

How to think about it: the relative clause modifies whatever noun it's touching. In the first sentence, who touches engineers. Adding only changes the meaning so that who now points back to one. Ask: "who is doing the verb — the whole group, or just this person?"

Trap 9 · Quantities, distances, amounts, and titles

The principle: when a plural-looking phrase names a single amount or a single thing, it's singular.

Twenty years is a long time to wait. one span of time

Three hundred dollars seems excessive.

The Grapes of Wrath was published in 1939. one book

Two-thirds of the budget has been spent.

Also: physics, mathematics, economics, news, statistics (the field), politics (the field), measles — all singular despite the -s. (Politics goes plural when it means someone's views: her politics are unorthodox.) And a few nouns are plural with no -s: people, children, men, women, criteria (sing. criterion), phenomena (sing. phenomenon), data (formally plural), media (sing. medium).

SVA checklist — 8 seconds per question

Find the verb.
Cross out every prepositional phrase, every comma-fenced chunk, every relative clause.
Ask "who/what verbs?" → subject.
Is the subject singular or plural? (Check the indefinite-pronoun list if it's one of those.)
Match. Remember: one -s between them.

8. Pronoun–antecedent agreement

The principle: a pronoun is a pointer. A pointer is useless if the reader can't tell what it points at, or if it points at something the wrong shape. So there are exactly three requirements:

A pronoun must be…

Unambiguous — exactly one possible antecedent.
Present — the antecedent must actually appear as a noun in the text.
Matched in number (and person, and case — case gets §9).

Requirement 1: unambiguous

When Marta met Diane, she was nervous. Which one? Unfixable without rewriting.

Marta was nervous when she met Diane.

The committee told the board that it had made an error. two singular groups — "it" could be either

On the SAT this usually shows up as: the "correct" answer replaces the pronoun with the actual noun. If two answer choices use pronouns and one names the noun, and there's genuine ambiguity — take the noun.

Requirement 2: the antecedent must exist as a noun

In Whitman's poetry, he celebrates the ordinary. "Whitman's" is possessive — it's functioning as an adjective, not a noun. There's no noun for "he" to point to.

In his poetry, Whitman celebrates the ordinary.

The council voted to rezone the waterfront, a decision that infuriated them. "them" means the residents — who are never mentioned. No noun, no pointer.

Requirement 3: number match

A company should treat their employees well.

A company should treat its employees well. companies, teams, committees, governments = "it," not "they" — this is the version the SAT really tests

Each of the museums has expanded their education programs.

Each of the museums has expanded its education programs. "each" is singular, so the pronoun must be too

All students must submit their essays by Friday. plural antecedent, plural pronoun — clean

Singular "they" — where the SAT actually stands

Generic singular they ("Every student must submit their essay") is now accepted by Chicago, AP, MLA and APA, and the digital SAT deliberately avoids items that hinge on it. You will not be asked to choose between their and his or her. A lot of prep material still teaches otherwise; ignore it.

What the SAT does test is the unambiguous stuff: it vs. they for an organization, and a pronoun that plainly mismatches a singular or plural noun. So the working rule is narrower than the one you were probably taught — match the pronoun to the grammatical number of its antecedent noun, and stay out of the singular-they debate entirely.

Person consistency

If one studies consistently, you will improve. third person → second person, mid-sentence

If you study consistently, you will improve.

If one studies consistently, one will improve.

9. Pronoun case (and who vs. whom)

The principle: English kept case marking only on pronouns. Case tells you the pronoun's job — subject, object, or possessor. It's a leftover agreement system, and it's the one where your ear will actively lie to you.

Subject (does the verb)	Object (receives / follows a preposition)	Possessive
I, we, he, she, they, who	me, us, him, her, them, whom	my/mine, our/ours, his, her/hers, their/theirs, whose

The compound trap

The award went to Priya and I.

The award went to Priya and me. Delete "Priya and": "went to me." Obvious.

Me and Jordan finished first.

Jordan and I finished first. Delete "Jordan and": "I finished first."

Technique: delete the other person. Your ear is fine with one pronoun; it panics with two. (People overcorrect to "I" because they were scolded for "me and Jordan" as kids — that's why "between you and I" sounds fancy and is wrong. Between is a preposition; prepositions take objects: between you and me.)

After comparisons: "than I" vs. "than me"

The comparison has an invisible verb. Restore it.

She runs faster than I [do]. "than I do" — I is a subject

The noise bothers Dev more than [it bothers] me. me is an object here

He likes pizza more than I / me. Both grammatical, different meanings: "more than I [like pizza]" vs. "more than [he likes] me."

Who vs. whom

The he/him substitution test

Isolate the clause the pronoun lives in. Rearrange it into normal order. Substitute:

fits he / she / they → who (both can end in a vowel sound; both are subjects)
fits him / her / them → whom (both end in m)

The scientist who discovered the enzyme won the prize. "HE discovered the enzyme" → who

The scientist whom the committee honoured had retired. "the committee honoured HIM" → whom

Give the file to whoever asks for it. Careful: the whole clause "whoever asks for it" is the object of "to." Inside that clause, "whoever" is the SUBJECT of "asks." → whoever

Shortcut

If the word is immediately followed by a verb, it's almost always who. If it's immediately followed by a noun or pronoun (a new subject), it's almost always whom. And whom is what you use straight after a preposition: to whom, for whom, with whom, of whom.

Its / it's, their / there / they're, whose / who's, your / you're

These are spelling, not grammar, but they're free points.

Word	Means	Test
`it's`	it is / it has	expand it. "It is raining" ✓
`its`	belonging to it	possessive pronouns never take apostrophes: his, hers, ours, theirs, its
`they're`	they are	expand it
`their`	belonging to them	possessive
`there`	place, or placeholder subject	contains "here"
`who's`	who is / who has	expand it
`whose`	belonging to whom	possessive
`you're`	you are	expand it
`your`	belonging to you	possessive

Part III · Verbs

10. The tense system, generated from two axes

You were probably handed a list of twelve tenses to memorize. Don't. There are two independent questions, and the twelve tenses are just the grid they produce.

Axis 1 — TIME: where is the reference point?

Past, Present, or Future. This is "when are we standing?"

Axis 2 — ASPECT: what shape is the event, seen from there?

Simple — just states it. A dot. walked
Perfect (have + past participle) — it happened before the reference point, and it still matters there. An arrow pointing back. had walked
Progressive (be + -ing) — it's in progress at the reference point. A line, not a dot. was walking
Perfect progressive — both: ongoing, and it started before the reference point. had been walking

	Simple	Perfect (before the reference point)	Progressive (during)	Perfect progressive
Past	I walked	I had walked	I was walking	I had been walking
Present	I walk	I have walked	I am walking	I have been walking
Future	I will walk	I will have walked	I will be walking	I will have been walking

Three times × four aspects = twelve. You never memorized twelve things; you memorized two.

What "perfect" actually means (this is the key insight)

Perfect = "before the reference point." That's all.

Present perfect (have walked): before now, still relevant now. I have lived here for ten years — and I still do.
Past perfect (had walked): before a past moment. Use it when you need to say "this happened even earlier than the past thing I just mentioned."
Future perfect (will have walked): before a future moment. By June I will have finished.

So the past perfect requires a past reference point in the sentence or nearby. If there isn't one, past perfect is wrong. That's the entire logic of the SAT's favorite verb-tense trap.

The Romans had built aqueducts across the empire. Had built BEFORE what? No second past event. Wrong.

The Romans built aqueducts across the empire.

By the time the legions withdrew, the Romans had built aqueducts across the empire. Now there's a reference point: the withdrawal. Building came before it.

I lived in Dubai since 2019. "since" = a stretch reaching to now → needs present perfect

I have lived in Dubai since 2019.

I lived in Dubai from 2019 to 2023. closed, finished period → simple past

11. Verb forms: the four principal parts

Every English verb has four forms, and the whole system is built from them:

Form	Regular	Irregular	Used for
Base / infinitive	walk	write, go, break	after to, after modals (can walk), and every present-tense form except third-person singular
Simple past	walked	wrote, went, broke	past tense — stands alone, never takes a helper
Past participle	walked	written, gone, broken	after have (perfect) and after be (passive) — can never be the main verb of a clause on its own
Present participle	walking	writing, going, breaking	after be (progressive); as adjective; as gerund (noun)

The rule that fixes almost every verb-form error

Simple past = alone. Past participle = with a helper.

More precisely: a past participle can't be the main verb of a clause without a helper. It is perfectly fine as a modifier, where it stands alone happily — a broken window, the fallen leaves, the theory proposed in 1912.

I seen it. "seen" is a participle — it needs a helper

I saw it. / I have seen it.

She had went home. "went" is simple past — it can't take a helper

She had gone home.

The window was broke.

The window was broken.

The irregulars the SAT actually uses

Base	Past	Participle	Base	Past	Participle
arise	arose	arisen	lie (recline)	lay	lain
begin	began	begun	lay (place)	laid	laid
break	broke	broken	ride	rode	ridden
choose	chose	chosen	rise	rose	risen
drink	drank	drunk	run	ran	run
drive	drove	driven	see	saw	seen
fly	flew	flown	shrink	shrank	shrunk
forget	forgot	forgotten	sing	sang	sung
freeze	froze	frozen	sink	sank	sunk
go	went	gone	speak	spoke	spoken
grow	grew	grown	swim	swam	swum
know	knew	known	take	took	taken
lead	led	led	throw	threw	thrown
leave	left	left	write	wrote	written

lie / lay — the one people never get

lie = to recline (you do it to yourself, no object): lie, lay, lain, lying. I lie down. Yesterday I lay down. I have lain down.
lay = to place something (needs an object): lay, laid, laid, laying. I lay the book on the table. Yesterday I laid it there.
The cruelty: the past of lie is spelled lay. Same for rise (no object) vs. raise (takes an object), and sit vs. set.

The verb-form errors the SAT plants

The company is capable to expand into three new markets. idiom error — "capable of expanding"

Having ate lunch, we returned to work.

Having eaten lunch, we returned to work.

The theory, first proposing in 1912, was rejected. passive meaning needs the PAST participle

The theory, first proposed in 1912, was rejected.

-ing vs. -ed participles: who's doing what

-ing (present participle) = active. The noun is doing it. the boiling kettle — the kettle boils.
-ed (past participle) = the noun receives the action, for any verb that takes an object. the boiled egg — someone boiled the egg. (For verbs that take no object, the participle just means "already happened": the fallen leaves, a retired teacher.)
So: an interesting book (the book does the interesting) vs. an interested reader (the reader receives it). A confusing question vs. a confused student.

12. Tense consistency and sequence

The principle: a passage establishes a timeline. Every verb has to be placed correctly on that timeline. So the question is never "which tense is correct in the abstract" — it's "what tense are the surrounding sentences in, and does this event happen before, during, or after them?"

Move #4 — Look outside the underlined portion

For any verb-tense question, read the sentence before and the sentence after. The non-underlined verbs are the answer key. The SAT cannot make them wrong, so they define the timeline. Match it unless there's a stated reason to shift.

Ferns reproduce by releasing spores. The spores germinate in damp soil, where they ___ into small heart-shaped plants.

…where they develop into small heart-shaped plants. The surrounding verbs are present tense (scientific general truth). Match.

Legitimate reasons to shift tense

A time marker demands it: in 1904, currently, by next spring, since, for the past decade, before that.
Sequencing two past events: the earlier one goes into past perfect. She realized she had left her keys inside.
Reported speech: present shifts back one step. He says he is tired → He said he was tired.
Convention: discussing what a text or artwork does uses present tense, even for old works. In Beloved, Morrison explores memory. Discussing the author's life uses past. Morrison published it in 1987.

Conditionals and the subjunctive (light touch — rarely tested)

Type	Pattern	Example
Real / likely	if + present, will + base	If it rains, we will cancel.
Unreal present	if + past (were), would + base	If I were taller, I would reach it.
Unreal past	if + past perfect, would have + participle	If she had studied, she would have passed.

Never "would have" in the if-clause

If I would have known, I would have called.

If I had known, I would have called.

Also: after demand, insist, require, suggest, recommend, propose, ask, request, essential/important that, use the bare base form: The board insisted that he resign (not "resigns"). It is essential that every form be signed. One exception worth knowing: when these verbs simply report a fact rather than issue a demand, they take ordinary tense — He insisted that he was innocent.

Part IV · Placement

13. Modifiers: proximity is meaning

The principle: English has almost no case endings, so it can't tell you what a modifier attaches to. It uses position instead. The convention is brutally simple:

The proximity rule

A modifier attaches to the nearest available noun. If the nearest noun isn't the one you meant, you have written something false — and the SAT will call it wrong regardless of whether a human could guess your intent.

Watch one word move and change the meaning five times:

Only she told him she loved him. Nobody else told him.

She only told him she loved him. She told him — she didn't show him.

She told only him she loved him. He's the only one she told.

She told him she only loved him. She loved him and did nothing more.

She told him she loved only him. He's the only one she loves.

Same five words. Five meanings. That's proximity doing the work of grammar.

The SAT's version: the opening modifier

By far the most tested placement question. The setup: a sentence opens with a descriptive phrase, a comma, then the main clause. The rule that follows directly from proximity:

The opening-modifier rule

When a sentence begins with a modifying phrase followed by a comma, the very first noun after the comma must be the thing that phrase describes.

So on these questions you don't evaluate all four answers. You do this: read the opening phrase, ask "who or what is doing this?", then find the answer choice that puts that noun first.

Walking through the museum, the sculptures seemed to glow. Who's walking? The sculptures. That's what the sentence literally says.

Walking through the museum, I noticed that the sculptures seemed to glow.

As I walked through the museum, the sculptures seemed to glow. Alternative fix: turn the phrase into a full clause with its own subject. Then there's nothing dangling.

Discovered in 1994 by three cavers, researchers have dated the paintings at Chauvet to 30,000 years ago. The researchers were not discovered in 1994.

Discovered in 1994 by three cavers, the paintings at Chauvet have been dated to 30,000 years ago.

A prolific inventor with over 1,000 patents, Edison's laboratory in Menlo Park became famous. The laboratory is not a prolific inventor. Possessives are the classic trap here — "Edison's" is not the same noun as "Edison."

A prolific inventor with over 1,000 patents, Edison made his Menlo Park laboratory famous.

Two things that make a dangling modifier invisible

Passive voice. ✗ After finishing the experiment, the samples were frozen. Samples don't finish experiments. Passive hides the actor, so the modifier has nothing to grab. If the main clause is passive and there's an opening modifier, check it immediately.
Possessives. Edison's laboratory, Curie's research, the band's debut — the head noun is laboratory / research / debut, not the person. A person-describing modifier can't attach to it.

Misplaced modifiers elsewhere in the sentence

The archivist found a letter in a drawer written by Lincoln. The drawer wasn't written by Lincoln.

The archivist found a letter written by Lincoln in a drawer.

She served sandwiches to the children on paper plates.

She served the children sandwiches on paper plates.

14. Parallelism

The principle: when you join items with a conjunction, you're saying "the same frame applies to all of these." A frame can only distribute over items of the same grammatical shape. So coordination requires matching structures — otherwise the frame doesn't fit and the reader's parser stalls.

The distribution test

Take the words before the list and mentally attach them to each item separately. If any version breaks, the list isn't parallel.

She enjoys hiking, kayaking, and to ride her bike. "She enjoys to ride" — breaks.

She enjoys hiking, kayaking, and riding her bike.

The internship taught me how to write clearly, how to manage deadlines, and the importance of asking questions. two "how to…" clauses + one plain noun phrase — the shapes don't match

The internship taught me how to write clearly, how to manage deadlines, and how to ask questions.

The soil was tested for lead, for arsenic, and mercury. If you repeat a preposition, repeat it for ALL items or NONE.

The soil was tested for lead, arsenic, and mercury.

Correlative conjunctions — the strictest case

These come in pairs, and whatever follows the first half must be the same shape as what follows the second: not only…but also, either…or, neither…nor, both…and, not…but, whether…or.

The policy not only reduced emissions but also it created jobs. verb phrase vs. full clause

The policy not only reduced emissions but also created jobs.

The policy not only reduced emissions but also stimulated job growth.

She was neither interested in the job or qualified for it. neither pairs with NOR, not OR

She was neither interested in the job nor qualified for it.

Fixed pairings: neither…nor, either…or, not only…but also, both…and, as…as, so…that, not so much…as, rather…than, prefer…to.

15. Logical comparison

The principle: a comparison is a claim about two things. If the two things aren't of the same kind, the claim is nonsense even when the grammar is fine. This is a logic error dressed up as a grammar error.

The population of Tokyo is larger than Berlin. comparing a population to a city

The population of Tokyo is larger than that of Berlin.

The population of Tokyo is larger than Berlin's. the possessive implies "Berlin's population"

Van Gogh's brushwork is more textured than most Impressionists.

Van Gogh's brushwork is more textured than that of most Impressionists.

The novels of Achebe, like Dickens, portray a society in transition.

The novels of Achebe, like those of Dickens, portray a society in transition.

The fix menu

Whenever a comparison has an unbalanced second half, the answer will contain one of: that of (singular), those of (plural), the possessive form (Berlin's), or a repeated noun (than the brushwork of…). Look for those words in the choices — they're a giveaway that this is a comparison question.

Comparative vs. superlative

Two things → comparative: -er or more. the taller of the two twins
Three or more → superlative: -est or most. the tallest player on the team
Never both: ✗ more taller, ✗ most fastest.
Between vs. among: between two, among three or more — though between is also right for several things related pairwise (a treaty between the five nations).
Number vs. amount: number / many / fewer for countable things; amount / much / less for uncountable stuff. fewer cars, less traffic

Excluding yourself from your own group

Delhi is larger than any city in India. Delhi is a city in India, so it'd have to be larger than itself.

Delhi is larger than any other city in India.

Delhi is the largest city in India.

Part V · Punctuation

16. The boundary problem

Here is the deep truth about punctuation, and once you have it, roughly a third of the test becomes arithmetic.

What punctuation is for

Speech has pauses, pitch changes, and stress to show you where one chunk ends and the next begins. Writing has none of that. Punctuation is the written substitute for those boundary signals.

So every punctuation question reduces to two sub-questions:

Is there a boundary here? (Do two structural units meet at this point?)
How strong is it? (Are the two units both full sentences, or is one subordinate to the other?)

The strength scale

weakest ─────────────────────────────────────────────────────── strongest nothing < comma < colon / dash < semicolon < period (,) (: —) (;) (.)

And the matching rule, which is the whole game:

Left of the mark	Right of the mark	What's allowed
Independent clause	Independent clause	`.` `;` `, +FANBOYS` `:` `—`
Independent clause	Fragment / phrase / list	`:` `—` `,` (or nothing)
Dependent clause	Independent clause	`,` (Because it rained, we left.)
Independent clause	Dependent clause	usually nothing (We left because it rained.)
Fragment	Fragment	usually nothing

Move #5 — The two-halves test

On any punctuation question:

Cover the punctuation. Read what's on the left. Could it be a sentence by itself? Yes / No.
Read what's on the right. Could it be a sentence by itself? Yes / No.
Look up the pair in the table above. Eliminate every choice that doesn't fit.

YES + YES is the money case: you need a period, semicolon, comma+FANBOYS, colon, or dash. A bare comma is always wrong there. That single fact kills a wrong answer on most punctuation questions.

The three failure modes with names

Comma splice: The hike was long, we finished at dusk. two independent clauses joined by a bare comma

Fused sentence / run-on: The hike was long we finished at dusk. no joiner at all

Fragment: Because the hike was long. a dependent clause standing alone

The hike was long; we finished at dusk.

The hike was long, so we finished at dusk.

Because the hike was long, we finished at dusk.

17. Commas: a closed list of five jobs

People think commas go "where you pause." That's why people get commas wrong. In formal written English the comma has exactly five jobs, and if a comma isn't doing one of them, it's an error. Learn the five and you can challenge every comma that isn't doing one of them.

Job 1 — Join two independent clauses, with a FANBOYS conjunction

For And Nor But Or Yet So. The comma goes before the conjunction. The comma alone can't do this job; the conjunction alone (in formal writing) can't either.

The bridge was closed, so we took the ferry.

The bridge was closed, we took the ferry.

The bridge was closed, so, we took the ferry.

Critical: if the second half is not an independent clause, you don't get the comma:

She revised the draft, and submitted it on Friday. "submitted it on Friday" has no subject — it's a compound verb, not a clause

She revised the draft and submitted it on Friday.

She revised the draft, and she submitted it on Friday.

Job 2 — Separate items in a list of three or more

The kit contains a compass, a whistle, and waterproof matches.

The kit contains a compass and a whistle. two items = no comma

The SAT always uses the Oxford comma (the one before "and") and never tests whether you should. It does test lists whose items contain their own commas — see semicolons, §19.

Job 3 — Set off an introductory element

Most things that come before the main clause get a comma after them — always a dependent clause, a participial phrase, or a transition word, and usually a long prepositional phrase. (A very short one often does without: In 1994 the team disbanded.)

After the votes were counted, the mayor conceded.

Exhausted by the climb, she sat down on a rock.

In the decades following the war, the city rebuilt.

However, the results were inconclusive.

Reverse the order and the comma usually disappears: The mayor conceded after the votes were counted. That's because a trailing dependent clause needs no boundary marker — the subordinator already told you what's coming.

Job 4 — Fence off non-essential information (the big one)

Extra information that could be lifted out without changing which thing you're talking about gets fenced by commas — on both sides, unless it sits at the very end of the sentence, where the period closes the fence for you: She sat down, exhausted by the climb. This is §18, and it deserves its own section.

Job 5 — Small conventional uses

Coordinate adjectives: a cold, damp cellar — test: can you swap them or insert "and"? If yes, comma. three old brick houses — can't swap → no commas.
Direct address: Neo, look at this.
Dates and places: July 4, 1776, was a Thursday. Austin, Texas, is growing. (note the closing comma — it's a fence, §18)
Contrast tags: The problem is structural, not cosmetic.
Quotation tags: She said, "Wait."

18. Restrictive vs. non-restrictive — the deepest idea in punctuation

This one rule generates more SAT questions than any other comma rule, and it's genuinely about meaning, not decoration.

The distinction

Restrictive (essential): the information narrows down which one you mean. Remove it and the reader no longer knows what you're talking about. → NO commas.

Non-restrictive (non-essential): the thing is already fully identified; the information is bonus. Remove it and the sentence still points at the same thing. → COMMAS on both sides.

Think of the commas as handles on a suitcase: they mark the chunk you could lift out.

The clearest demonstration — same words, two different worlds:

My sister who lives in Oslo is a doctor. NO commas → restrictive → I have several sisters, and I'm telling you which one.

My sister, who lives in Oslo, is a doctor. COMMAS → non-restrictive → I have one sister. Oslo is a side note.

Neither is "more correct." They mean different things. The SAT usually gives you enough context to know which is intended, and the answer choices are often all four combinations of comma placement.

What makes something automatically non-essential

A proper name has already identified the thing. You can't narrow down a unique individual.
Marie Curie, who won two Nobel Prizes, died in 1934.
Marie Curie who won two Nobel Prizes died in 1934. implies there are several Marie Curies
Appositives after a specific noun.
The keynote speaker, an epidemiologist from Lagos, spoke for an hour.
"which" clauses. In American formal usage, which = non-restrictive (commas), that = restrictive (no commas).
The proposal that the board approved will take effect in July. tells you which proposal
The proposal, which the board approved in May, will take effect in July. bonus info about a known proposal
The proposal which the board approved will take effect in July.

What makes something automatically essential

A general noun that needs narrowing. Students who submit late work lose ten percent. — remove it and the sentence is false about all students.
An indefinite / counted noun before a name. The novelist Zadie Smith was born in London. — "the novelist" alone doesn't identify anyone, so the name is essential → no commas. Compare: Her favorite novelist, Zadie Smith, was born in London. — "her favorite novelist" is already unique → commas.

The delete test

Cover the phrase. Read the sentence without it. Ask: "Do I still know exactly which thing this sentence is about?"

Yes, still clear → non-essential → two commas
No, now vague or now false → essential → zero commas

The one-comma error — the SAT's favorite

Fences come in pairs. If you open with a comma you must close with one, and vice versa. Look at the unpunctuated side of an underlined comma: that's usually where the error is hiding.

The report, which took eight months to compile was released Tuesday.

The report which took eight months to compile, was released Tuesday.

The report, which took eight months to compile, was released Tuesday.

The report that took eight months to compile was released Tuesday.

The same pairing applies to dashes and parentheses — and you cannot mix the fence types: ✗ The report — which took eight months, was released.

19. Colons, dashes, semicolons

Colon — "here it comes"

The one requirement

Whatever is to the LEFT of a colon must be a complete sentence. Whatever's to the right can be anything: a list, a phrase, a single word, or another full sentence.

Function: the left half makes a promise, the colon says "delivery incoming," the right half delivers — an explanation, an example, a list, or a definition.

She had one condition: total creative control.

The cause was finally clear: a hairline crack had formed in the weld. right side is a full clause — that's fine

Pack three things: a headlamp, spare batteries, and a map.

The three things you need are: a headlamp, batteries, and a map. "The three things you need are" is not a complete sentence

The kit includes: rope, chalk, and tape. same problem — never put a colon right after a verb or a preposition

Fast check: if the word right before the colon is are, is, includes, such as, like, for example, of, to — it's almost certainly wrong.

Dash — the flexible one

The dash has two distinct jobs, and the SAT tests both:

Single dash = a stronger colon. Left side must be a complete sentence; right side is an amplification, a reversal, or a punchline.
The vote was unanimous—all forty members agreed.
She trained for two years—and then broke her ankle a week before the race.
Paired dashes = a stronger pair of commas. Fences off non-essential material, especially when that material already contains commas.
Three species—the axolotl, the olm, and the mudpuppy—retain larval features into adulthood. commas would be ambiguous here; dashes keep the fence visible

Don't mix fence types

The device—a prototype from the 1970s, still works.

The device—a prototype from the 1970s—still works.

The device, a prototype from the 1970s, still works.

Semicolon — a period with a hyphen in its relationship

Two jobs, both strict

Join two closely related independent clauses. Both sides must be complete sentences. If you can't swap in a period, you can't use a semicolon.
Super-comma: separate list items that already contain commas.

The trial ended early; the evidence was overwhelming.

The trial ended early; therefore, sentencing was moved up. conjunctive adverbs need the semicolon, §3

The trial ended early; because the evidence was overwhelming. right side is dependent

The panel included Dr. Osei, a virologist; Ms. Lindqvist, an epidemiologist; and Mr. Baptiste, a statistician.

Semicolon vs. colon vs. dash, when both sides are sentences

All three are grammatically legal. They differ in relationship:

Semicolon — the two clauses are equals, closely related. Balanced.
Colon — the second clause explains or answers the first. Directional.
Dash — the second clause surprises, reverses, or dramatizes. Emphatic.

On the SAT, if two choices are both grammatically fine, the test almost always includes only one — so if you find yourself choosing between a legal semicolon and a legal colon, re-read: usually one of them has a fragment on a side you didn't check carefully.

20. Where commas are forbidden

Just as useful as knowing where commas go. If a comma isn't doing one of the five jobs, delete it. These are the four places the SAT plants illegal commas:

1. Never split a subject from its verb

The rusted iron gate at the end of the lane, creaked in the wind.

The rusted iron gate at the end of the lane creaked in the wind.

Exception: a pair of commas fencing non-essential material may sit between them. One comma may not.

2. Never split a verb from its object or complement

The committee announced, that the deadline had moved.

Scientists have discovered, a new species of deep-sea coral.

Scientists have discovered a new species of deep-sea coral.

3. Never put a comma before an essential (restrictive) modifier

Anyone, who arrives after 9 a.m. will be marked late.

Anyone who arrives after 9 a.m. will be marked late.

The city banned cars, built before 1998.

4. Never comma between a compound verb / compound object

She opened the drawer, and pulled out a map.

She opened the drawer and pulled out a map.

He studied physics, and chemistry.

Also: no comma between adjective and noun (✗ a long, winding, road), and no comma before a preposition just because the sentence feels long.

The "no punctuation" answer

On the digital SAT, one choice is frequently no punctuation at all, and it is right more often than students expect — because the default state of a sentence is unpunctuated. Punctuation must earn its place. When in doubt and no rule applies: take the option with fewer marks.

21. The apostrophe grid

The principle: plurality and possession are two independent facts about a noun. So there are four combinations, and the apostrophe's position encodes which one you mean. Stop thinking of it as a list of rules; think of it as a 2×2 grid.

	Not possessive	Possessive
Singular	`dog` the dog barked	`dog's` the dog's collar (one dog)
Plural	`dogs` the dogs barked	`dogs'` the dogs' collars (several dogs)

How to build any possessive, mechanically

Write the noun in the number you mean (dog or dogs; child or children).
Add 's.
Only if the word is a plural that already ends in -s (dogs's), drop the second s → dogs'.

That handles the irregular plurals automatically: children → children's, women → women's, people → people's — none of them ends in -s, so step 3 never fires.

Singular nouns that already end in -s keep the extra s: James's car, the boss's office, the class's average, Dickens's novels. Step 3 applies to the plural -s only. (Newspaper style drops it — James' — but Chicago, MLA and the SAT keep it.)

the student's essay one student

the students' essays many students

the children's books "children" is already plural

the company's policy / the companies' policies

The 1990's were a decade of change. plain plural — no apostrophe

The 1990s were a decade of change.

Several painting's were stolen.

Several paintings were stolen.

Possessive pronouns never take apostrophes

its, his, hers, ours, yours, theirs, whose — all apostrophe-free. They're already possessive; the apostrophe would be redundant. Any apostrophe in one of those words means it's a contraction instead: it's = it is, who's = who is, they're = they are.

The 10-second apostrophe algorithm

Is the word a pronoun (its/their/whose/your)? → apostrophe only if you can expand it to two words.
Does something belong to this noun? (Can you rewrite with "of"? the dog's collar = the collar of the dog) → No = no apostrophe, you just have a plural.
If yes: write the noun in the number you mean, add 's, then drop the final s only if the word was already a plural ending in -s. (dog → dog's; dogs → dogs'; children → children's; boss → boss's)

Part VI · Words

22. Prepositions, derived as far as they can be

Prepositions feel like pure memorization. They're about 70% derivable and 30% arbitrary, and it's worth knowing which part is which.

The derivable part: prepositions are spatial primitives, extended by metaphor

Every preposition starts as a picture of physical space. Abstract uses are that picture applied to a non-physical thing. Once you see the picture, most uses stop feeling random.

Preposition	Physical picture	The metaphor extension
in	inside a container / bounded region	enclosed states & periods: in trouble, in 1994, in April, in a hurry, in Spanish, interested in
on	contact with a surface	topics you rest on, days as flat units: on the table, on Monday, a book on physics, rely on, based on
at	a point, no interior	precise times & targeted attention: at 3 p.m., at the corner, aim at, good at, arrive at
to	path toward a goal	recipients, comparisons, attachments: give to, listen to, similar to, prefer X to Y
from	path away from a source	origins & separations: from Lagos, differ from, prevent from, derived from
for	facing / in exchange for	purpose & beneficiary: a gift for you, famous for, responsible for, wait for
with	accompaniment / holding	instrument & association: cut with a knife, agree with, familiar with, consistent with
by	beside / via a path	agent & method & deadline: written by, by train, by Friday
of	part broken off a whole	belonging, composition, content: the roof of the house, made of oak, aware of
about	around, encircling	subject matter & approximation: a film about war, about forty people
over / under	vertical position	authority, quantity, duration: over budget, under pressure, over the years
between / among	in the gap of two / mixed into many	between us two, among the crowd
through / across	path entering and exiting / traversing a surface	through the process, across cultures

Notice how in / on / at for time follow the same logic as for space: at a point in time (3 p.m.), on a flat one-day unit (Monday, June 3), in a container of time you can be inside (April, 1994, the morning, two hours).

The arbitrary part: frozen idiom

Some pairings froze centuries ago and the metaphor is no longer visible. Why "interested in" but "fascinated by"? Why "different from" but "similar to"? No useful reason. These you memorize — but the good news is the SAT recycles a small set, listed next.

23. The idiom list the SAT actually recycles

Correct	Correct	Correct
abide by	familiar with	preferable to
accuse of	focus on	prohibit from
adhere to	grateful to (person) / for (thing)	protect from / against
agree with (person) / to (plan)	identical to	rely on
aim to (do)	independent of	responsible for
apply to (school) / for (job)	indifferent to	result in (effect) / from (cause)
associate with	insist on	similar to
capable of	interested in	subscribe to
characteristic of	native to	substitute for
comply with	object to	succeed in
consist of	opposed to	sympathize with
consistent with	participate in	tolerant of
contrast with	preoccupied with	vary from
depend on	prevent from	wary of
differ / different from	preferable to	worry about

Six that get "corrected" wrong

different than →

✓ different from

prefer X over Y → ✓ prefer X to Y

try and finish → ✓ try to finish

the reason is because → ✓ the reason is that

not only… but — fine in real English (not only did it pass, but it passed unanimously); SAT answer keys still pair not only with but also

in regards to → ✓ in regard to / with regard to

Two of these are SAT preferences rather than absolute errors: different than and prefer X over Y are both recorded as standard by major American dictionaries. On the test, take from and to anyway.

24. Confusable words the SAT plants

Pair	Difference
affect / effect	affect = verb, to influence. effect = noun, the result. (Rare: effect as a verb = to bring about.) Action = affect.
than / then	than = comparison. then = time or consequence.
fewer / less	countable / uncountable. fewer bottles, less water
number / amount	same split. a number of errors, an amount of rainfall
between / among	two / three or more. Exception: between is correct for several items related pairwise — a treaty between the five nations.
lie / lay	recline (no object) / place something (object). See §11.
rise / raise	go up by itself / lift something else
accept / except	receive / excluding
allusion / illusion	indirect reference / false appearance
complement / compliment	completes something / praise
principal / principle	main, or head of school / a rule or belief
cite / site / sight	quote / place / vision
elicit / illicit	draw out / illegal
precede / proceed	come before / go forward
farther / further	physical distance / degree or extent
imply / infer	the speaker implies; the listener infers
e.g. / i.e.	for example / that is (in other words)

25. Transitions — reduce words to relations

Transition questions look like vocabulary. They aren't. There are only about seven logical relations two sentences can have. Identify the relation from the content, then pick the word. Never pick the word by feel.

Move #6 — Cover the transition

Physically ignore the blank and the answer choices. Read the sentence before and the sentence after. Then say out loud, in your own plain words, how they relate: "the second one contradicts the first" or "the second one is the result of the first." Only now look at the choices and find the word that means that. This converts a fuzzy question into a matching exercise.

Relation	Signal words
Addition — more of the same direction	also, moreover, furthermore, in addition, additionally, similarly, likewise
Contrast — opposite direction	however, but, yet, nevertheless, nonetheless, on the other hand, in contrast, conversely, still, instead, rather, whereas, while
Cause — pointing back to a reason	because, since, for, due to, owing to, as
Effect — pointing forward to a result	therefore, thus, consequently, as a result, hence, accordingly, so
Example — a specific case of the general claim	for example, for instance, to illustrate, in particular (namely and specifically are subtly different — they name the whole set, not a sample)
Concession — admitting a point before pushing back	admittedly, granted, to be sure, of course, certainly (the push-back that follows takes a contrast word: even so, that said, still, nonetheless)
Sequence / time	first, next, then, meanwhile, subsequently, finally, previously, eventually, afterward
Restatement / emphasis	in other words, that is, indeed, in fact, put simply
Conclusion	in short, in sum, ultimately, overall, on the whole

Four things that make transition questions go wrong

Reading only the sentence with the blank. The relation lives between two sentences. You must read both.
Confusing cause and effect direction. Because points backward to the reason; therefore points forward to the result. If you flip them the sentence still sounds smooth, which is why this trap works. Ask: which sentence is the reason and which is the result?
Treating "however" and "moreover" as interchangeable filler. They're opposites: one reverses direction, one continues it.
Picking a transition that repeats a relation already stated. If the sentence already says "although," you don't also need "however."

Solar panel costs fell nearly 90 percent between 2010 and 2020. ___, installation rates in many regions remained flat, largely because of permitting delays.

Nevertheless / However Cheaper should mean more installs. It didn't. That's a reversal → contrast.

Consequently would mean flat installs were the RESULT of falling costs. Backwards.

26. Rhetorical synthesis ("student notes" questions)

These aren't grammar at all — they're a reading-comprehension task wearing a grammar costume. You get a bulleted list of notes and a stated goal. Every one of them is solved the same way:

The three-step method

Read the goal sentence FIRST, before the notes. It's the last line of the prompt, and it's the only thing that matters. Underline the key words — "emphasize a difference," "explain the purpose of X to someone unfamiliar with it," "introduce the study to an audience already familiar with the topic."
Convert the goal into a checklist of required elements. "Emphasize a similarity between the two studies" → the answer must (a) mention both studies and (b) state a similarity. Two boxes to tick.
Eliminate on the checklist, not on truth. Every choice will be factually accurate — they're all copied from the notes. Wrong answers are wrong because they achieve a different goal, not because they're false. That's the whole trick.

Common goal types and what they demand:

Goal wording	The answer must contain
"emphasize a similarity"	both items + an explicit point they share
"emphasize a difference / contrast"	both items + an explicit contrast word or contrasting facts
"introduce X to an audience unfamiliar with it"	a definition or basic identification of X — no jargon assumed
"…to an audience already familiar with X"	skips the definition; goes straight to the new point
"explain the purpose / goal of the study"	a why, not a what — look for in order to, aimed to, sought to
"present the finding / result"	an outcome, usually with data
"make a generalization"	a broad claim, not a specific data point

Timing note: these are the slowest questions per point on the test. If you're short on time, do them last.

Part VII · Execution

27. The attack algorithm

On the digital SAT, Standard English Conventions questions have no question stem — just a sentence with a blank and four choices. That's a gift: the answer choices tell you which rule is being tested. Read them first as a diagnostic.

Step 0 — Diagnose from the choices

If the choices differ in…	The rule being tested is…
is / are, has / have, was / were, or verb -s	subject–verb agreement (§6–7)
tense forms of one verb	tense & sequence (§10, §12) — go read the surrounding sentences
its / their / it's, or pronoun swaps	pronoun agreement or case (§8–9)
apostrophe positions on one word	plural vs. possessive (§21)
commas, semicolons, colons, dashes, periods	boundaries (§16) — do the two-halves test immediately
the same words in different orders	modifier placement (§13) — check the opening phrase
totally different connecting words	transitions (§25) — cover the blank, name the relation
whole different sentences, plus a stated goal above	rhetorical synthesis (§26)

The full sequence, per question (target: 35–45 seconds)

Scan the four choices. Name the rule. (2 sec)
Read the whole sentence, including past the blank to the period. Most errors reveal themselves only at the end.
Strip decoration. Cross out prepositional phrases, comma-fenced chunks, relative clauses. Find the skeleton.
Apply the specific test for that rule (two-halves, delete-test, he/him, distribute-the-frame…).
Eliminate, don't select. Kill choices for a stated reason. If you can't name why a choice is wrong, you haven't found the rule yet.
Plug the survivor back in and read the sentence whole.

Three habits that raise scores more than any rule

Never choose by sound. If you catch yourself thinking "this one flows better," stop and find the rule. The SAT engineers wrong answers to sound smooth and right answers to sound stiff.
Shortest correct answer wins ties. When two choices are both grammatically legal, the SAT prefers the concise, non-redundant one. Wordiness is treated as an error.
Read past the blank. The most common careless error is choosing a verb before noticing the sentence continues with a second clause.

28. What the SAT does NOT test (stop worrying about these)

Knowing the boundary saves real time.

Spelling (except the its/it's, their/they're family, which is really grammar).
Capitalization.
The Oxford comma as a choice — it's always used, never debated.
Split infinitives — to boldly go is fine.
Ending a sentence with a preposition — fine.
Starting a sentence with "and" or "but" — fine.
Passive voice as an error — passive is not wrong. It's only a problem when it creates a dangling modifier.
Hyphens in compound modifiers — essentially never tested.
Semicolon vs. colon as a style judgment — only one will be grammatically legal.
Vocabulary difficulty in conventions questions — the words are always common.
"Which sounds more formal" — the test is about structure, not register.

29 · Practice bank

Thirty-two questions in digital-SAT format. Before you reveal an answer, force yourself to say the name of the rule out loud. If you can't name it, you got it right by luck, and luck doesn't transfer to test day.

Set A · Subject–verb agreement

Question 1

The archive of letters, diaries, and ship manifests compiled by nineteenth-century customs officials ______ the most complete record of the port's trade.

are
is
have been
were

B — is

Rule: subject–verb agreement across an interrupting prepositional phrase.

Strip it: of letters, diaries, and ship manifests is a prepositional phrase; compiled by nineteenth-century customs officials is a participial phrase. Neither can contain the subject. Skeleton: archive ______ the record. Archive is singular → is. The three plural nouns sitting right before the verb are bait.

Question 2

Neither the two lead engineers nor the project manager ______ willing to sign off on the revised timeline.

were
have been
was
are

C — was

Rule: neither…nor takes the number of the nearer subject.

The nearer subject is the project manager — singular. So was. If the order were reversed (neither the project manager nor the two lead engineers), the answer would be were. The rule is positional, which feels arbitrary until you remember or means "only one of these is actually true."

Question 3

Beneath the layers of plaster applied during the building's 1950s renovation ______ a series of medieval frescoes.

lies
lie
have lain
are lying

A — lies

Rule: inverted order, then strip the prepositional phrase. Two traps stacked.

Trap 1: the sentence opens with a prepositional phrase, so the subject comes after the verb. Rebuild it in normal order: ______ a series of medieval frescoes beneath the layers of plaster.

Trap 2: now that the subject is visible, strip it. The subject is a series — singular. Of medieval frescoes is a prepositional phrase and cannot contain the subject. So: a series lies.

Compare a series of X (singular — one series) with the quantity words in Q5: most of X takes X's number, but a series of X does not, because "a series" is a real countable noun, not a portion word. B, C and D are all plural, so all three die on the same rule.

Question 4

Each of the seventeen countries that signed the accord ______ obligated to report emissions annually.

are
were
have been
is

D — is

Rule: each is always singular.

Each is the subject; of the seventeen countries is a prepositional phrase; that signed the accord is a relative clause modifying countries. Both are decoration. Each is.

Question 5

Roughly three-quarters of the museum's textile collection ______ never been displayed publicly.

have
has
are having
were having

B — has

Rule: fractions and quantity words (some, most, half, three-quarters, all, none) take the number of the noun in the of-phrase.

The noun is collection — singular → has. Compare: Three-quarters of the textiles have never been displayed. This is the one legitimate case where you look inside the prepositional phrase, and it's derivable: a fraction takes the number of the stuff it's a fraction of.

Set B · Pronouns

Question 6

The conservation society announced that ______ would fund three new wetland reserves before the end of the decade.

they
it
them
these

B — it

Rule: collective / organizational nouns are singular in American usage.

Society, committee, company, government, team, band, university → it and its, never they and their. This is one of the highest-frequency pronoun errors on the test precisely because everyday speech does the opposite.

Question 7

The grant will be divided between Dr. Halvorsen and ______, who together lead the isotope lab.

I
myself
me
mine

C — me

Rule: pronoun case after a preposition.

Delete the other person: divided between… me. Between is a preposition, so it takes the object form. "Between you and I" sounds educated and is wrong for exactly this reason. And myself is a reflexive — it's only legal when the subject and object are the same person (I taught myself) or for emphasis (I built it myself).

Question 8

The historian ______ archive the university purchased had cataloged every document by hand.

who's
whose
whom
which

B — whose

Rule: possessive relative pronoun.

The archive belongs to the historian → possessive → whose. Who's expands to "who is," which gives nonsense: the historian who is archive. And which can't refer to a person.

Question 9

The finalists were told that ______ time trial results would be posted by 5 p.m. Friday.

there
they're
their
there're

C — their

Rule: possessive pronoun vs. its homophones.

The results belong to the finalists → possessive → their, and finalists is plural, so the number matches too. Expand-test the rest: B gives "they are time trial results," which says something entirely different; A is a place or a placeholder subject; D isn't a form you should ever write.

Note what this question is not testing. A version with "Anyone hoping to qualify must submit ______ results" would hinge on singular they, and the digital SAT deliberately avoids that fight. Don't go looking for it.

Question 10

In Rachel Carson's 1962 book Silent Spring, ______ documented the ecological damage caused by synthetic pesticides.

she
her
Carson
who

C — Carson

Rule: a pronoun's antecedent must be a noun, and a possessive doesn't count.

Carson's is possessive — it's doing adjective work, modifying book. So there is no noun for she to point back to. B is an object pronoun sitting in a subject slot — wrong twice over. D would turn the main clause into a relative clause and leave the whole sentence a fragment. Only the name works. This is the same underlying issue as the possessive dangling-modifier trap in §13.

Set C · Verbs

Question 11

By the time rescuers reached the summit ridge, the storm ______ for nearly eleven hours.

rages
has raged
had been raging
is raging

C — had been raging

Rule: past perfect progressive — ongoing action that began before a specific past reference point.

Rescuers reached establishes a past reference point. The storm was already going on before it and continued up to it, so you need had been + -ing. "By the time…" is a near-guaranteed signal for past perfect.

Question 12

The Antikythera mechanism, recovered from a shipwreck in 1901, ______ the earliest known analogue computer.

had been
is
was being
will be

B — is

Rule: tense choice by meaning — a fact that remains true takes present tense.

The mechanism still is the earliest known analogue computer; the statement is a standing fact, not a past event. Past perfect (A) is wrong because there's no second past event for it to precede — a bare had been with no reference point is almost always a wrong answer.

Question 13

Having ______ the manuscript three times, the editor still found two inconsistencies in the timeline.

read
readed
reading
reads

A — read

Rule: having + past participle.

The perfect participle construction requires the past participle form. For read, all three principal parts are spelled the same (read / read / read) — pronunciation changes, spelling doesn't. Compare the same structure with write: Having written…, never Having wrote….

Question 14

The review board recommended that the proposal ______ resubmitted with a full cost breakdown.

is
was
be
will be

C — be

Rule: the subjunctive after verbs of demand or recommendation.

After recommend, demand, insist, require, request, suggest, propose, ask — and after it is essential/important/necessary that — the verb in the that-clause goes into its bare base form, with no agreement and no tense. …that the proposal be resubmitted, …that he resign, …that she arrive early. Lightly tested, but free points when it appears.

Set D · Boundaries and punctuation

Question 15

The reservoir had dropped to twelve percent of capacity ______ the city imposed mandatory restrictions the following week.

, and
,
and,
; and,

A — , and

Rule: two independent clauses need a legal joiner.

Two-halves test: left = The reservoir had dropped to twelve percent of capacity → complete sentence. Right = the city imposed mandatory restrictions the following week → complete sentence. YES + YES, so a bare comma (B) is a comma splice. C and D put a comma after the conjunction, which is never correct.

Question 16

Tidal turbines are far more predictable than wind turbines ______ they can be scheduled into the grid with unusual precision.

, therefore
; therefore,
therefore
, therefore,

B — ; therefore,

Rule: conjunctive adverbs have no joining power.

Both halves are complete sentences, so you need a real joiner. Therefore is an adverb, not a conjunction — it can't hold two clauses together no matter how many commas you give it. A semicolon (or a period) does the joining; the comma after therefore is the standard introductory comma. Test the word: "They can therefore be scheduled…" — it floats freely inside its clause, which proves it's an adverb.

Question 17

Only one material met every requirement ______ a titanium alloy developed for deep-sea submersibles.

; and
:
;
, and

B — :

Rule: colon = complete sentence on the left, delivery on the right.

Left side is a complete sentence. Right side is a noun phrase, not a clause — and that one fact kills three choices at once. C (semicolon) and D (comma + and) both demand a full sentence on the right; A isn't a legal construction at all. The colon is the only mark that takes a complete sentence on the left and accepts anything on the right. The first half makes a promise ("one material") and the second half delivers it.

A dash would also have been legal here — which is exactly why the test didn't offer one. If you ever find two legal marks among the choices, re-read: you've almost certainly mis-scanned one side.

Question 18

The 1815 eruption of Mount Tambora ______ which ejected roughly 150 cubic kilometers of rock ______ cooled global temperatures for three years.

, / ,
— / ,
, / —
no punctuation / no punctuation

A — , / ,

Rule: fences come in matching pairs.

which… introduces a non-restrictive clause (the eruption is already uniquely identified by date and mountain), so it must be fenced. And you cannot mix fence types: a dash must close with a dash, a comma with a comma. B and C are the classic mismatched-fence trap. D removes the fence entirely, which would make the clause restrictive — implying there were several 1815 eruptions of Tambora and this is the one that ejected 150 km³.

Question 19

Students ______ who complete the fieldwork module ______ receive credit toward the environmental science certificate.

, / ,
, / no punctuation
no punctuation / ,
no punctuation / no punctuation

D — no punctuation / no punctuation

Rule: restrictive (essential) clauses take no commas.

Delete test: Students receive credit toward the certificate. That's now a claim about all students — false, and not what was meant. The clause narrows down which students, so it's essential, so no commas. Contrast Q18, where deleting the clause left the meaning intact.

Question 20

The geologist Marie Tharp mapped the mid-Atlantic ridge ______ her work provided some of the first physical evidence for continental drift.

,
and,
;
: and

C — ;

Rule: two independent clauses; only a full-strength joiner works.

A is a comma splice. B puts the comma after the conjunction, which is never correct — ", and" would have been fine, but that isn't what's on offer. D isn't a thing. The semicolon works and signals the close relationship between the mapping and its significance.

Also worth noticing: Marie Tharp takes no commas here, because "the geologist" alone doesn't identify anyone — the name is essential. If it read "Tharp, a geologist, mapped…", commas would be required.

Question 21

The expedition carried three instruments ______ a magnetometer, a sonar array, and a set of sediment corers.

:
;
,
, and

A — :

Rule: colon introducing a list after a complete sentence.

The expedition carried three instruments stands alone → colon is legal. B fails because the right side isn't a sentence. C fails for a concrete reason: the list items are themselves separated by commas, so an introducing comma blurs the line between "here comes the list" and "here's the next item." D reads as though a fourth instrument were being added.

Compare the illegal version: ✗ The expedition carried: a magnetometer, a sonar array, and corers. Here the left side ends on a verb and isn't a sentence — never put a colon straight after a verb.

Question 22

Because the permafrost has begun to thaw much earlier each spring ______ engineers have had to redesign the pipeline's support pilings.

no punctuation
,
;
:

B — ,

Rule: a dependent clause placed before the main clause is followed by a comma.

Because downgrades the first clause, so this is dependent + independent — which takes a comma, not a semicolon or colon (both of those want a complete sentence on the left). Reverse the order and the comma disappears: Engineers have had to redesign the pilings because the permafrost has begun to thaw earlier.

Set E · Modifiers, parallelism, comparison

Question 23

Trained as a cellist before turning to composition, ______

Rebecca Clarke's viola sonata won wide acclaim in 1919.
the viola sonata Rebecca Clarke wrote in 1919 won wide acclaim.
Rebecca Clarke wrote a viola sonata that won wide acclaim in 1919.
it was Rebecca Clarke's 1919 viola sonata that won acclaim.

Rule: the opening-modifier rule — the first noun after the comma must be who's doing the modifier.

Who was trained as a cellist? Rebecca Clarke. So the main clause must start with Rebecca Clarke. A starts with Rebecca Clarke's — possessive, so the actual head noun is sonata, and sonatas don't train as cellists. B starts with the viola sonata. D starts with it. Only C puts the right noun in the right slot.

Note the method: you never had to evaluate the choices as sentences. You asked one question and matched one noun. That's 10 seconds instead of 60.

Question 24

The new curriculum asks students to analyze primary sources, to construct evidence-based arguments, and ______

presenting findings to a public audience.
to present findings to a public audience.
they must present findings publicly.
the presentation of findings publicly.

Rule: parallelism in a list.

Distribute the frame: asks students to analyze… ✓ / asks students to construct… ✓ / asks students to present… ✓. The first two items are infinitive phrases, so the third must be too. A is a gerund, C is a full clause, D is a noun phrase — each breaks the frame.

Question 25

The migratory range of the Arctic tern is far greater than ______

any other bird.
other birds.
that of any other bird.
any bird.

Rule: logical comparison — compare like to like.

The left side of the comparison is the migratory range, not the tern. So the right side must also be a range, not a bird. That of stands in for "the migratory range of." A and B compare a range to birds. D additionally fails the self-exclusion rule — the tern is a bird, so it can't have a greater range than "any bird" including itself; you need any other.

Question 26

The restoration team not only stabilized the fresco's plaster substrate ______ the pigments' original saturation.

but also recovered
but they also recovered
and also recovered
but also they recovered

A — but also recovered

Rule: correlative conjunctions require matching structures on both sides.

not only is followed by a bare verb phrase (stabilized the substrate), so but also must be followed by a bare verb phrase too (recovered the saturation). B and D insert a new subject, turning the second half into a clause — mismatched. C breaks the fixed pairing: not only pairs with but also, never with and also.

Question 27

Scanned with ground-penetrating radar over three winters, ______

archaeologists identified two buried structures at the site.
the site revealed two previously unknown buried structures.
two buried structures were what archaeologists found.
there were two buried structures identified at the site.

Rule: opening modifier — and note the passive-voice trap.

What was scanned with radar? The site. Not the archaeologists (A), not the structures (C — the structures were found by scanning, they weren't the thing being scanned), and D opens with the empty placeholder there, which can never be the thing a modifier describes. B puts the site immediately after the comma.

Set F · Apostrophes and word choice

Question 28

Both ______ nesting sites were destroyed when the levee failed.

colony's
colonies
colonies'
colonies's

C — colonies'

Rule: plural possessive.

Build it mechanically: both tells you there are two colonies → write the plural, colonies → add 's → colonies's → double s, so drop the second → colonies'. A means one colony. B is a plain plural with no possession, which leaves nesting sites with no owner. D is the un-simplified form.

Question 29

The committee released ______ findings in March, though ______ still unclear whether the recommendations will be adopted.

its / its
it's / it's
its / it's
their / it's

C — its / it's

Rule: possessive pronoun vs. contraction, plus collective-noun agreement.

First blank: the findings belong to the committee → possessive → its, no apostrophe. Expand-test: "the committee released it is findings" is nonsense. Second blank: it is still unclear works → it's. D fails because a committee is singular in American usage.

Question 30

Because the new filtration system removes sediment continuously, the plant now produces ______ waste sludge and requires ______ maintenance shutdowns per year.

less / fewer
fewer / less
less / less
fewer / fewer

A — less / fewer

Rule: countable vs. uncountable.

Sludge is a mass noun — you can't have "three sludges" — so less. Shutdowns are discrete countable events, so fewer. Same logic governs amount (uncountable) vs. number (countable), and much vs. many.

Set G · Transitions

Question 31

Coral reefs cover less than one percent of the ocean floor. ______, they support roughly a quarter of all marine species.

Consequently
Nevertheless
For example
Similarly

B — Nevertheless

Rule: identify the relation before looking at the words.

Cover the blank and paraphrase: "reefs take up almost no space" / "but they hold a huge share of species." Tiny area would predict few species; the second sentence overturns that expectation. That's contrast. A reverses the logic into cause-and-effect. C would require the second sentence to be a specific instance of the first — it isn't. D claims the two facts point the same way — they don't.

Question 32

Lidar surveys can penetrate dense forest canopy and record the ground surface beneath it. ______, archaeologists working in Guatemala mapped more than sixty thousand previously undocumented Maya structures in a single season.

However
Consequently
In contrast
Regardless

B — Consequently

Rule: name the relation before you look at the words.

Cover the blank and paraphrase in your own words: "lidar can see through the canopy" → "so archaeologists found sixty thousand hidden structures." Sentence 1 is the capability; sentence 2 is what that capability produced. That's cause → effect.

Naming the relation kills three choices in one move: A and C both signal reversal, and D signals that the second fact holds despite the first. Notice that you never compared the four words to each other — you decided what you needed, then went shopping. That's the entire method.

After you finish

Go back through every question you missed and write one line in this format:

Q18 — mismatched fences — I checked the first comma and never looked at the second — test to run: if I see one comma, look for its partner.

30. One-page cheat sheet

The four ideas

A sentence = subject + finite verb. Everything else is decoration.
Only a finite verb makes a clause. -ing, to-forms, and bare participles don't.
Two independent clauses need one of: . ; , +FANBOYS : — or a subordinator.
Commas fence removable information — in pairs, never singly.

Situation	Do this
Verb agreement	Cross out prepositional phrases → find real subject → match. One -s per pair.
There is / There are	Flip the sentence; the subject follows the verb.
Each, every, neither, anyone	Singular. Always.
Some / most / none / all / half of…	Agree with the noun after "of."
Team, committee, company, government	Singular → it, not they.
A or B	Agree with the nearer one.
Past perfect (had + participle)	Only if there's a second, later past event.
Simple past vs. participle	Past stands alone; participle needs a helper. saw / have seen.
Opening phrase + comma	Next noun must be who's doing the phrase.
Punctuation choice	Left side a sentence? Right side a sentence? Look up the pair.
Comma splice	Two full sentences + bare comma = always wrong.
However, therefore, moreover	Need a semicolon or period before them, not a comma.
Colon	Left side must be a complete sentence. Never after are, includes, such as.
One comma appears	Check if it needs a partner. Fences come in pairs.
Name already identifies the noun	Following description gets commas.
that vs. which	that = no commas, essential. which = commas, extra.
Apostrophe	Owner singular → `'s`. Owner plural → `s'`. Just plural → nothing.
its / it's	Expand to "it is." Works? it's. Doesn't? its.
Pronoun in a pair	Delete the other person and listen.
who / whom	he → who. him → whom. (Both end in m.)
List or pair with a conjunction	Distribute the opening words over each item.
Comparison	Compare like to like — look for that of / those of / 's.
Transition	Cover it. Name the relation in your own words. Then match.
Notes question	Read the goal first. Turn it into a checklist. Eliminate on the goal, not on truth.
Two choices both legal	Take the shorter one.

A three-week practice plan, if you want one

Week 1 — Foundations. Do nothing but identify subject and finite verb in 10 sentences a day from any book. No questions, just labelling. This builds the perception that everything else depends on.
Week 2 — One rule per day. Read one section here, then do 10–15 targeted questions on that rule only (Khan Academy's practice sets are organized this way). Massed practice on one rule builds recognition faster than mixed sets.
Week 3 — Mixed sets + an error log. Now mix. For every miss, write one line: the rule, why I fell for it, the test I should have run. Re-read the log before each session. Most people miss the same four rules over and over; the log is what makes that visible.

Built for Neo. Every example sentence here was written from scratch — none are copied from the College Board or Khan Academy, so use this alongside their official practice sets rather than instead of them. The fastest gains come from Part I plus an error log; the rest is lookup.