SAT Grammar Rules Guide

The 12 rules

1. Independent vs. dependent clauses

Two independent clauses cannot be joined with just a comma (that's a comma splice). Use a period, semicolon, or comma + FANBOYS (for, and, nor, but, or, yet, so).

✗ The lab was crowded, we waited outside.
✓ The lab was crowded, so we waited outside.
✓ The lab was crowded; we waited outside.

2. The semicolon = period rule

A semicolon must have a complete sentence on each side. If you can't replace it with a period, it's wrong.

3. The colon = "such as" rule

A colon must follow a complete sentence and is used to introduce a list, explanation, or quote.

✓ She brought three items: a notebook, a pen, and tea.

4. Subject–verb agreement

Find the real subject (ignore prepositional phrases). Singular subject → singular verb.

The box of cookies is on the table. (not "are")

5. Pronoun agreement

Pronouns must match their antecedent in number. "Everyone", "each", and "anyone" are singular.

6. Modifier placement

A descriptive phrase at the start of a sentence must describe the subject that immediately follows.

✗ Running to the bus, my backpack fell open.
✓ Running to the bus, I felt my backpack fall open.

7. Parallel structure

Items in a list or comparison must share the same grammatical form.

✗ She likes hiking, swimming, and to bike.
✓ She likes hiking, swimming, and biking.

8. Verb tense consistency

Don't switch tenses unless the meaning requires it. If the sentence is in the past, keep it in the past.

9. Pronoun case (who vs. whom, I vs. me)

Use subject pronouns (I, he, she, who) for subjects; object pronouns (me, him, her, whom) for objects of verbs or prepositions.

10. Apostrophes

• It's = it is. Its = belongs to it.
• The dog's bone = singular possessive.
• The dogs' bones = plural possessive.

11. Transition words

The SAT loves to test transitions: "however", "therefore", "in addition", "for example". Ask: does the next sentence agree, contrast, or cause?

• Agree / add: also, furthermore, moreover, in addition
• Contrast: however, nevertheless, on the other hand
• Cause: therefore, thus, as a result, consequently
• Example: for instance, for example, specifically

12. Rhetorical synthesis

You're given a bullet list of notes and asked which sentence best fulfills a goal (e.g., "introduce the topic" or "emphasize a contrast"). Strategy: identify the goal, then pick the answer that uses words from the bullets in the right relationship.

The 30-second check

For every Writing question, ask in this order:

1. Is each clause complete?
2. Does the verb match the subject?
3. Does the pronoun match its antecedent?
4. Does the modifier touch the right noun?
5. Does the transition match the logic?

Practice it

• Practice quiz #1
• Practice quiz #2