Standard English Conventions rulebook

SAT Grammar Rules for the Digital SAT

Learn the decision behind each major punctuation and usage pattern, see a correct example beside its most tempting trap, and move directly into the matching practice skill.

Start with the answer choices

The two official skill groups

College Board groups Standard English Conventions questions into two skills. Comparing the choices before rereading the sentence helps you choose the right decision process.

3 rules below

Boundaries

The answer choices differ in punctuation. Identify the clauses first; then decide whether they should be separated, joined, or set off.

Open Boundaries practice

6 rules below

Form, Structure, and Sense

The answer choices differ in words or sentence structures. Find the subject, timeline, antecedent, modifier, or parallel pattern the sentence requires.

Open form and structure practice

Rule → example → trap → practice

Nine rules to make explicit

Do not choose by sound alone. Name the rule, eliminate choices that violate it, and confirm that the completed sentence says what its context requires.

Rule 1

Sentence boundaries

Boundaries

Rule: First classify each clause. Join two independent clauses with a period, a semicolon, or a comma plus a coordinating conjunction; do not leave a dependent clause standing alone.
Correct example: The forecast changed; the team revised its plan.
Trap to avoid: The forecast changed, the team revised its plan. A comma alone creates a comma splice between two complete sentences.

Practice this skill

Rule 2

Commas

Boundaries

Rule: Use commas after introductory elements, around nonessential information, between list items, and before a coordinating conjunction that joins two independent clauses. Do not split a subject from its verb.
Correct example: After the samples arrived, the researchers labeled, sorted, and stored them.
Trap to avoid: The researchers, labeled the samples. The comma incorrectly separates the subject from its verb.

Practice this skill

Rule 3

Semicolons, colons, and dashes

Boundaries

Rule: A semicolon needs an independent clause on both sides. A colon or single dash follows a complete clause and introduces an explanation, example, or list. Paired dashes can set off nonessential information.
Correct example: The team needed one item—a calibrated scale. The backup—which the team had packed separately—was still at camp.
Trap to avoid: The missing item was—a calibrated scale incorrectly puts a single dash after an incomplete lead-in. The scale—that the team needed—was at camp incorrectly sets off essential information with paired dashes.

Practice this skill

Rule 4

Subject–verb agreement

Form, Structure, and Sense

Rule: Match the verb to the grammatical subject, not to a nearby noun inside a prepositional phrase, appositive, or relative clause.
Correct example: The collection of essays is available online. Collection is the singular subject.
Trap to avoid: The plural noun essays sits closer to the blank, but it is not the subject of the verb.

Practice this skill

Rule 5

Verb tense and form

Form, Structure, and Sense

Rule: Use time markers and surrounding verbs to establish the timeline, then choose the finite verb form that expresses the intended sequence or ongoing fact.
Correct example: By the time the lecture began, the technicians had tested the projector.
Trap to avoid: The technicians have tested conflicts with the completed past sequence established by began and by the time.

Practice this skill

Rule 6

Pronouns

Form, Structure, and Sense

Rule: A pronoun needs a clear antecedent and must use the case, person, and number required by its role in the sentence.
Correct example: The researchers submitted their findings after they verified the calculations.
Trap to avoid: When Maya called Priya, she shared the result. She could refer to either person, so the reference is ambiguous.

Practice this skill

Rule 7

Modifiers

Form, Structure, and Sense

Rule: Place a modifying phrase next to the word it logically describes. An introductory modifier must describe the grammatical subject that immediately follows it.
Correct example: Walking through the archive, Lena noticed a handwritten map.
Trap to avoid: Walking through the archive, a handwritten map caught Lena’s attention. The map is not doing the walking.

Practice this skill

Rule 8

Parallelism

Form, Structure, and Sense

Rule: Items that perform the same job in a list, comparison, or paired construction should use matching grammatical forms.
Correct example: The team planned to collect, analyze, and report the data.
Trap to avoid: To collect, analyzing, and report mixes an infinitive pattern with a gerund.

Practice this skill

Rule 9

Possessives and apostrophes

Form, Structure, and Sense

Rule: Use an apostrophe to show possession or a contraction, not to make a noun plural. Distinguish possessive its from the contraction it’s.
Correct example: The researchers’ notes recorded the instrument’s settings.
Trap to avoid: The experiment lost it’s control group. It’s means it is; the possessive form is its.

Practice this skill

Test-day grammar checklist

Run only the checks relevant to the choices. The goal is a short, repeatable decision—not a full grammatical analysis of every sentence.

1Compare the answer choices: punctuation differences usually signal Boundaries; word or structure differences usually signal Form, Structure, and Sense.
2Bracket the clauses and decide which ones can stand alone before choosing punctuation.
3Check whether a comma is doing one of its actual jobs, not merely marking a pause you hear.
4Find the grammatical subject before checking the verb, and ignore intervening phrases.
5Build the sentence timeline from time markers and surrounding verbs.
6Trace every pronoun to one clear antecedent and check its grammatical role.
7Place modifiers next to the words they describe and compare the forms in every list.
8Decide whether a noun is plural, possessive, or both before placing an apostrophe.
9Read the complete sentence with your choice inserted and confirm both grammar and meaning.

Turn the rules into retrieval practice

Read once, then practice. For each miss, write the smallest rule that would have produced the right answer and test that rule again later.

Open the grammar domain guideSee the complete Standard English Conventions map and its two skill groups.Add section strategy and pacingUse the Reading and Writing guide for question recognition, order, and time decisions.Build a targeted question setFilter the practice library, solve without the explanation, and record the rule behind each miss.Test the rules under timeApply the checklist in a timed section, then review every uncertain answer.Turn misses into a review queueClassify each error, write a correction rule, and schedule a later retrieval check.