The rules the SAT actually tests
Good news: the SAT grammar categories are public. The Standard English Conventions questions cover sentence structure and boundaries (run-ons, fragments), punctuation (commas, semicolons, colons, dashes, apostrophes), agreement (subject-verb, pronoun-antecedent), verb tense and form, and modifiers. Expression of Ideas questions cover transitions, concision, and logical sentence placement.
That's it. You do not need to name grammatical terms like a linguistics professor — you need pattern recognition on about a dozen rules. Each rule shows up in nearly identical disguise every test, which makes grammar the most learnable, highest-ROI section of SAT prep. Two weeks of focused drilling routinely moves students 40+ points on Reading & Writing.
- Boundaries: fixing run-ons, comma splices and fragments
- Punctuation: commas, semicolons, colons, dashes, apostrophes
- Agreement: subjects with verbs, pronouns with antecedents
- Verbs: tense consistency and correct forms
- Expression of Ideas: transitions, concision, sentence order
Punctuation: the highest-value rules
Learn commas by their jobs: they separate items in lists, set off extra information, and follow introductory phrases. They cannot join two complete sentences — that's a comma splice. To join two complete sentences you need a semicolon, a colon (when the second explains the first), a dash, or a comma plus a conjunction like 'and,' 'but' or 'so.' The colon rule trips the most students: what comes before a colon must be a complete sentence, and what follows elaborates — a list, definition or explanation.
Apostrophes are simpler than they look: use them for possession ('the student's book'; 'the students' books' for plural owners) and in contractions — never for simple plurals. When a choice offers 'its' versus 'it's,' expand the apostrophe into 'it is' and listen: if 'it is' makes no sense in the sentence, you want 'its.' That two-second test settles every its/it's, their/they're and whose/who's question ever written.
- Comma splice: two full sentences joined by only a comma — always wrong
- Semicolon: joins two complete, related sentences with no conjunction
- Colon: complete sentence before; a list, definition or explanation after
- Dashes work in pairs like parentheses to set off extra information
- Its vs it's: expand to 'it is' — if it fits, use the apostrophe
'Maria collected soil samples for weeks, the data surprised her advisor.' Two complete sentences, comma alone = comma splice. Fixes: '...for weeks; the data surprised...' or '...for weeks, and the data surprised...' or '...for weeks. The data surprised...' Recognizing that both halves are complete sentences is the whole battle.
Agreement, verbs and modifiers
For subject-verb agreement, find the true subject and ignore everything sandwiched between it and the verb. In 'The box of nails (were/was) heavy,' the subject is 'box,' not 'nails' — the prepositional phrase 'of nails' is camouflage. Same trick for pronouns: 'Each of the students left (their/his or her) notebook' — 'each' is singular, so match it. Scan for singular culprits like 'each,' 'every,' 'either' and 'neither.'
Dangling modifiers are wrong because the sentence never names who's doing the action. 'Walking to school, the rain soaked my jacket' claims the rain was walking. The fix is putting the real actor right after the comma: 'Walking to school, I was soaked by the rain.' If an underlined phrase describes an action, the very next words must name the person doing it.
- Cross out prepositional phrases to expose the true subject
- 'Each,' 'every,' 'either,' 'neither' are singular — match verbs accordingly
- Tense should stay consistent unless the timeline genuinely shifts
- Dangling modifier: the doer of the opening phrase must follow the comma
- Pronouns must match their antecedent in number and clarity
Transitions and concision: the logic points
Transition questions test logic, not vocabulary. Read the two sentences, decide their relationship first — continuation ('similarly,' 'in addition'), contrast ('however,' 'nevertheless'), cause-effect ('therefore,' 'as a result'), or illustration ('for example') — then pick the matching choice. Deciding the relationship before looking at the answers is what keeps a fancy word like 'nonetheless' from seducing you when the logic is simple addition.
Concision questions ask which answer 'most effectively' completes the sentence, and the shortest grammatical answer is very often right — the test writers love redundancy like 'return back' and 'annual yearly tradition.' But shortest is a tiebreaker, not a law: the answer must first be grammatical and preserve the meaning. Kill redundancy, keep the meaning, and the point is yours.
- Decide the sentence relationship before reading the choices
- Contrast: however, nevertheless, in contrast
- Cause-effect: therefore, thus, as a result
- Redundancy kills: 'return back,' 'each individual person,' 'future plans'
- Concision rule: shortest answer that is grammatical AND keeps the meaning
Key concepts to memorize
🎯 Study tips for this topic
- Memorize the four fixes for comma splices (semicolon, colon, period, comma + conjunction) until spotting them is reflex.
- Do 10 punctuation questions a day for a week — volume builds the pattern recognition these questions reward.
- When checking agreement, physically cross out prepositional phrases in the booklet or on scratch paper.
- For transition questions, write your own connector ('CONTRAST,' 'THEREFORE') in the margin before reading choices.
- Drill the flashcards below until you can name each rule in under five seconds — speed here buys time for reading questions.
