SAT Grammar Rules: The Complete List for the Digital SAT

The digital SAT tests a short, predictable list of grammar rules in its Standard English Conventions questions: sentence boundaries and punctuation, subject-verb agreement, pronoun agreement, verb tense and form, plurals and possessives, and modifier placement. Learn the dozen or so rules below and you will be able to answer these questions quickly and with confidence, since the same rules repeat on every test.

How is grammar tested on the digital SAT?

Grammar falls under the Standard English Conventions domain, about 26 percent of the Reading and Writing section. Each question shows a short passage with a blank and asks which choice "conforms to the conventions of Standard English."

The domain has two skill areas:

There are no "find the error" or "no change" questions on the digital SAT. Every grammar question is a fill-in-the-blank with four versions of the same words.

Boundaries rules (punctuation)

These get a full guide of their own in SAT Boundaries questions. The essentials:

1. Two independent clauses must be joined by a period, a semicolon, a comma plus a FANBOYS conjunction (for, and, nor, but, or, yet, so), or a colon when the second explains the first.
2. A comma alone cannot join two independent clauses. That is a comma splice.
3. However, therefore, moreover, and similar words need a semicolon or period before them when they start a new clause.
4. A colon must follow a complete independent clause.
5. Nonessential phrases are set off with matching punctuation on both sides: two commas, two dashes, or two parentheses.
6. Essential information takes no commas. "The poet Langston Hughes" has no commas.
7. No comma between a subject and its verb or between a verb and its object.

Subject-verb agreement

Rule: a singular subject takes a singular verb; a plural subject takes a plural verb.

The SAT makes this hard by separating the subject from the verb with a long phrase.

The collection of letters written by the poet's sisters ______ on display at the museum.

A) are B) were C) is D) have been

Cross out the prepositional phrase "of letters written by the poet's sisters." The subject is collection, which is singular. Answer: C.

Other agreement traps:

• Each, every, either, neither, everyone, nobody are singular: "Each of the samples was tested."
• Compound subjects joined by and are plural: "The mayor and the council are meeting."
• Inverted sentences: find the subject after the verb. "Among the ruins were several clay tablets." The subject is tablets.

Pronoun agreement and case

Rule: a pronoun must agree in number with the noun it replaces.

• Wrong: The company announced that they would expand.
• Right: The company announced that it would expand.

Collective nouns like company, team, committee, and jury are singular on the SAT.

Also know which pronouns are which:

A quick test for its versus it's: replace the word with "it is." If the sentence breaks, you need its.

Verb tense and verb form

Rule: keep tense consistent with the time frame of the passage unless the context shows a change.

In 1905, Einstein published four papers that ______ physics.

A) transform B) will transform C) transformed D) are transforming

The passage describes a completed past event. Answer: C.

The SAT also tests finite versus nonfinite verbs, meaning whether a sentence has a real main verb.

• Wrong: The researchers, after months of fieldwork, collecting samples from the river.
• Right: The researchers, after months of fieldwork, collected samples from the river.

If a sentence has a subject but only an -ing form or to form where the main verb should be, it is a fragment. This is one of the most frequent Form, Structure, and Sense questions.

Plurals and possessives

Rules:

• A plural noun with no ownership has no apostrophe: the scientists.
• A singular possessive adds 's: the scientist's notebook.
• A plural possessive ending in s adds only an apostrophe: the scientists' notebooks.
• A plural possessive not ending in s adds 's: the children's books.

The ______ findings were published in two separate journals.

A) researcher's B) researchers C) researchers' D) researchers's

"Two separate journals" suggests more than one researcher, and the findings belong to them. Answer: C.

Check whether the next word is something being owned. If it is, you need an apostrophe; if it is a verb, you do not.

Modifier placement

Rule: an introductory modifying phrase must be followed immediately by the noun it describes.

• Wrong: Having studied the fossils for years, the discovery surprised the paleontologist.
• Right: Having studied the fossils for years, the paleontologist was surprised by the discovery.

The discovery did not study fossils, so the first version is a dangling modifier. On the SAT, the blank usually begins right after the comma, and the correct answer starts with the person or thing doing the action.

What grammar is not tested much?

The digital SAT spends little or no time on obscure rules like the subjunctive mood, split infinitives, or ending sentences with prepositions. Concision and word choice belong to other question types: Words in Context tests vocabulary, and Transitions tests logical connections between sentences.

How to study SAT grammar efficiently

1. Learn one rule at a time with a small set of practice questions.
2. Label every miss by rule: comma splice, agreement, possessive, modifier.
3. Look for patterns. Most students lose points on two or three rules, not all of them.
4. Mix rules in timed sets once each is solid, because the real test does not tell you which rule a question targets.

How Ivystar can help

Grammar questions are a finite set of rules, so they are where focused prep pays off fastest. In Ivystar SAT Prep, a tutor identifies exactly which rules cost you points and drills them until they are automatic; students improve by an average of 170 points. Start with a free practice SAT or book a free 20-minute strategy call.