SAT Grammar Rules

La méthode, étape par étape

1. 1

   Learn how independent clauses may be joined

   period · semicolon · comma + FANBOYS conjunction · colon (when the second explains)

   Two complete sentences cannot be joined by a comma alone — that is a comma splice, and it is the most tested error on the section. Knowing the four legitimate joins makes a large share of questions immediate.

2. 2

   Match verbs to their actual subject

   'the box of books is heavy' — subject is box, not books

   Test writers separate subject from verb with intervening phrases, so the noun nearest the verb is often not the subject. Crossing out the intervening phrase leaves the agreement obvious.

3. 3

   Check pronouns have one clear antecedent

   'it' must refer to exactly one identifiable noun

   A pronoun with two possible referents is ambiguous, and ambiguity is an error even when the sentence reads naturally. Pronoun number must match too — a singular noun takes a singular pronoun.

4. 4

   Place modifiers next to what they modify

   'Walking home, the rain started' → the rain was not walking

   An opening participial phrase modifies whatever noun follows the comma. If that noun cannot logically perform the action, the modifier is dangling — and this is tested nearly every form.

5. 5

   Use the shortest option that is correct

   when two options are both grammatical, prefer the concise one

   Where several answers are grammatically acceptable, the SAT prefers the one without redundancy. Options repeating an idea already stated are wrong even when nothing is technically ungrammatical about them.

The list really is finite

Unlike reading comprehension, which cannot be studied to completion, the conventions tested here are a closed set. Clause joining, subject-verb agreement, pronoun clarity and agreement, verb tense consistency, modifier placement, apostrophes, and the comma, semicolon, colon and dash. That is essentially all of it.

This makes it the highest-return area of the whole test for most students. A few weeks of focused work converts a category of questions from guesswork into near-certainty, which is not true of any other part of the SAT.

• Four ways to join independent clauses
• Subject-verb agreement across intervening phrases
• Pronoun clarity and number
• Modifier placement — no dangling participles
• Apostrophes: possession versus contraction
• Concision preferred among correct options

The most tested error

Joining two complete sentences with a comma is the single most frequently tested error. The fix is one of four things: a full stop, a semicolon, a comma plus one of the FANBOYS conjunctions, or a colon if the second sentence explains the first.

The reliable test is to cover the punctuation and ask whether both halves could stand alone as sentences. If both can, a comma alone is wrong — and that question takes two seconds.

Derive the rule rather than memorising cases

Students often learn a list of situations where commas appear. This works until an unfamiliar sentence structure arrives, at which point there is no case to match against. Understanding why a semicolon joins two independent clauses generalises to every sentence.

It is also more durable under exam pressure. A derived rule can be reconstructed; a memorised list of cases degrades, and it degrades fastest under exactly the conditions the test creates.

How we teach SAT grammar

We start here in almost every SAT course, because it is finite and it moves the score quickly, which builds the confidence needed for the slower reading work.

We teach each rule by derivation rather than by case list. Students who can say why a semicolon works where it does handle sentence structures they have never seen, which is what the test actually presents them with.