Summary of Grammar
Notes
Key points
- Stops (. ; , + FANBOYS) join two full sentences; a comma alone never does.
- Half-stops (: —) need a complete sentence before them.
- Non-essential info: two matching marks. Essential info: none.
- No punctuation between subject–verb, verb–object, title–name, or after “such as”.
- Verbs: find the true subject, match number, keep the passage's tense.
- Pronouns: match the antecedent; its / their / whose never take an apostrophe.
- Transitions: name the relationship first, then check clause vs noun phrase.
Rules
Two independent clauses: period, semicolon, or comma + FANBOYS.
The lab closed; the staff moved.
The lab closed, the staff moved.
Colon or dash only after a complete sentence.
He needed one tool: a wrench.
He needed: a wrench.
The verb agrees with the true subject.
The cost of repairs is high.
The cost of repairs are high.
Singular noun, singular pronoun.
The museum opened its new wing.
The museum opened their new wing.
An opening modifier describes the subject right after it.
Walking home, Ana saw a fox.
Walking home, a fox was seen by Ana.
No comma between subject and verb.
The oldest tree in the park fell.
The oldest tree in the park, fell.
Common traps
- Punctuating where you'd pause — the SAT tests structure, not breath.
- Two choices doing the same job (period vs semicolon, thus vs therefore): eliminate both.
- Choosing by sound when a ten-second rule check would settle it.
SAT tip
Every Conventions question: see what changes across the choices, name the rule, apply it, move on.
Test yourself
10 official SAT questions on Summary of Grammar, easiest first.