SAT Grammar Rules: The Complete Conventions Guide
Standard English Conventions questions make up roughly 11-14 questions per SAT Reading and Writing section, split between Form Structure and Sense (grammar) and Boundaries (punctuation). Unlike reading comprehension, grammar questions have objectively correct answers based on specific rules. If you learn the rules, you can answer these questions quickly and confidently. This guide covers every grammar rule the SAT tests.
Subject-Verb Agreement
The subject and verb must match in number. The SAT makes this tricky by inserting phrases between the subject and verb. Rule: Ignore prepositional phrases, relative clauses, and appositives between the subject and verb. Find the true subject. Example: 'The collection of rare manuscripts [is/are] housed in the library.' The subject is 'collection' (singular), not 'manuscripts,' so the verb is 'is.' Watch for: inverted sentences where the subject comes after the verb, compound subjects joined by 'or' (verb matches the nearest subject), and indefinite pronouns (each, every, neither = singular).
Verb Tense and Consistency
The SAT tests whether you can choose the correct tense based on time markers and surrounding context. Rules: Use past tense for completed actions ('yesterday,' 'in 1920,' 'last year'). Use present tense for ongoing truths or current states. Use present perfect ('has studied') for actions starting in the past and continuing. Use past perfect ('had finished') for actions completed before another past event. Most importantly: maintain tense consistency within a passage unless a clear time shift occurs.
Modifier Placement
A modifier must be placed next to the word it describes. The SAT tests dangling and misplaced modifiers. Rule: An introductory participial phrase must modify the subject immediately following the comma. Wrong: 'Running through the park, the trees provided shade.' (Trees are not running.) Correct: 'Running through the park, the jogger appreciated the shade from the trees.' On the SAT, check: does the subject after the comma logically perform the action described in the opening phrase?
Pronoun Agreement and Clarity
Pronouns must agree with their antecedents in number and be unambiguous. Rules: A singular noun takes a singular pronoun. 'Each student should bring his or her book' (or restructure to avoid the issue). A pronoun must clearly refer to one specific noun. If two nouns could be the antecedent, the reference is ambiguous and the sentence needs revision. The SAT frequently tests this with 'they' referring to a singular antecedent or an unclear 'it' that could refer to multiple things.
Parallel Structure
Items in a list or comparison must have the same grammatical form. Wrong: 'The researcher enjoys collecting data, analyzing results, and to write reports.' Correct: 'The researcher enjoys collecting data, analyzing results, and writing reports.' The SAT tests parallelism in lists (all gerunds, all infinitives, all nouns), in comparisons ('more X than Y' where X and Y are parallel), and in correlative conjunctions ('both A and B,' 'neither A nor B,' 'not only A but also B').
Boundaries: Semicolons
A semicolon connects two complete independent clauses that are closely related. Rule: Both sides of a semicolon must be able to stand alone as complete sentences. Wrong: 'The study was groundbreaking; which changed the field.' ('Which changed the field' is not a complete sentence.) Correct: 'The study was groundbreaking; it changed the field.' The SAT also tests semicolons before transitional phrases: 'The data was inconclusive; however, the team published preliminary results.'
Boundaries: Colons
A colon introduces a list, explanation, or restatement. The key rule: the clause before the colon must be a complete independent clause. Wrong: 'The ingredients include: flour, sugar, and eggs.' (Remove the colon or restructure.) Correct: 'The recipe requires three ingredients: flour, sugar, and eggs.' The SAT tests whether students know that a colon must follow a complete sentence and that what follows can be a list, a single word, a phrase, or another complete sentence.
Boundaries: Commas and Comma Splices
The SAT tests three main comma rules. Rule 1: Do not join two independent clauses with only a comma (comma splice). Use a comma + conjunction, a semicolon, or a period. Rule 2: Use commas to set off nonessential (nonrestrictive) information. 'The researcher, who joined the team last year, led the study.' Rule 3: Use commas after introductory phrases. 'After the experiment concluded, the team analyzed the data.' Do NOT use a comma between a subject and its verb or between a verb and its direct object.
Boundaries: Dashes and Parenthetical Phrases
Dashes set off parenthetical information with more emphasis than commas. The SAT rule: if a dash opens a parenthetical phrase, a dash must close it (unless the phrase ends the sentence). Wrong: 'The study — which lasted three years, produced unexpected results.' Correct: 'The study — which lasted three years — produced unexpected results.' This matching principle (two dashes or two commas around a parenthetical) is one of the most commonly tested boundary rules.
How to Approach Grammar Questions on Test Day
Step 1: Read the full sentence including all answer choices. Step 2: Identify what rule is being tested (subject-verb agreement? punctuation? modifier?). Step 3: Apply the specific rule. Step 4: Check that your chosen answer does not create a new error. Grammar questions should take 30-45 seconds each. If you know the rules, they are among the fastest points on the SAT. Study one rule category at a time, drill 15-20 questions on that rule, then move to the next. After covering all rules, mix practice to build recognition speed.
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