← Back to Blogs

Mastering SAT Grammar and Punctuation

Published on August 30, 2025·10 min read

The Punctuation Toolkit

You only need to know a few punctuation marks for the SAT, but you need to know them perfectly.

1. Commas

Commas have four main jobs on this test:

  • Lists: Separating three or more items. (I like dogs, cats, and birds.)
  • Introductions: After an introductory word, phrase, or clause. (Yesterday, I went to the store.)
  • Non-essential Info: A pair of commas can "hug" extra details. The sentence must still make sense if you remove the part in the middle. (My friend, who is a doctor, is smart.)
  • With FANBOYS: To separate two complete sentences. (I was tired, so I went to bed.)

2. Apostrophes

  • Possession: Shows ownership.
    • Singular: the dog's toy
    • Plural: the dogs' toys
    • Irregular Plural: the children's toys
  • Contractions: Replaces missing letters.
    • it's = it is
    • they're = they are
    • who's = who is

The Golden Rule for Pronouns: The contraction (it's, they're, who's) ALWAYS gets the apostrophe. The possessive form (its, their, whose) NEVER does. This is tested constantly.

3. Semicolons (;)

A semicolon is a "super period." It connects two closely related, complete sentences. If you can use a period, you can use a semicolon.

  • The test was hard; I still think I did well.

4. Colons (:)

A colon is a "gateway." It introduces something.

The Golden Rule for Colons: A colon must come after a complete sentence.

  • Introduce a list: I need three things: milk, bread, and eggs.
  • Provide an explanation: He had one great fear: public speaking.

5. Dashes (—)

Dashes are versatile.

  • A pair of dashes can replace a pair of commas to hug non-essential info.
  • A single dash can replace a semicolon or a colon for dramatic emphasis.

Key Sentence Structure Rules

Modifiers

A descriptive phrase at the beginning of a sentence must describe the noun that comes immediately after the comma.

  • WRONG: Running quickly, the finish line was crossed by the athlete. (The finish line wasn't running.)
  • RIGHT: Running quickly, the athlete crossed the finish line.

Verbs (Agreement & Tense)

  • The "Odd Verb Out" Trick: For subject-verb agreement, look at the answer choices. One verb will usually be singular (talks) while the others are plural (talk). The one that's different is almost always the answer. Test it with "he" (singular) and "they" (plural).
  • Tense Consistency: If the trick doesn't work, it's a tense question. Look at the other verbs in the paragraph to make sure the tense is consistent (e.g., past, present).

Pronouns

A pronoun (it, he, they, their) must agree with the noun it replaces.

  • Find the pronoun.
  • Find the noun it's replacing.
  • Make sure they match in number (singular/plural). Ignore any distracting phrases in between.