SAT Grammar Rules: The 7 Rules That Appear on Every Single Test

Why Grammar Questions Are the Easiest to Master

Unlike comprehension or vocabulary questions that require inference and judgment, grammar questions on the SAT follow fixed, learnable rules. There are about 14 grammar questions per test, and knowing these 7 rules will get you 11–12 of them correct.

Rule 1: Comma Splice (Most Common Error)

A comma splice joins two independent clauses with only a comma. It's always wrong on the SAT.

❌ Wrong: She studied hard, she scored 1400.

✅ Fix options:

• Period: She studied hard. She scored 1400.
• Semicolon: She studied hard; she scored 1400.
• Conjunction: She studied hard, so she scored 1400.

Rule 2: Semicolons and Colons

Semicolons connect two independent clauses. What comes after must be a complete sentence.

Colons introduce a list or explanation. What comes before must be a complete sentence; what comes after doesn't need to be.

Rule 3: Apostrophes for Possession

Singular possession: the student's score (one student)
Plural possession: the students' scores (multiple students)
Possessive pronoun its has no apostrophe. It's = it is.

Rule 4: Subject-Verb Agreement with Intervening Phrases

The verb must agree with its subject, not with a nearby noun.

Example: The results of the study were surprising. (Subject = results, not study)

Watch for: "one of those who," "each," "neither...nor," "either...or" — these often trick students.

Rule 5: Pronoun-Antecedent Agreement

Pronouns must agree in number with the noun they refer to.

❌ Each student brought their book. (Technically incorrect, though commonly accepted)

✅ Each student brought his or her book.

The SAT often tests singular "they" — in recent tests, it accepts "they" for a singular gender-neutral antecedent.

Rule 6: Parallel Structure

Items in a list must all have the same grammatical form.

❌ She likes running, to swim, and dance.

✅ She likes running, swimming, and dancing.

Rule 7: Modifier Placement

A modifier must be placed next to the word it modifies. Misplaced modifiers are a classic SAT trap.

❌ Walking into the room, the furniture seemed old. (The furniture wasn't walking)

✅ Walking into the room, I noticed the furniture seemed old.