Approximately 12–15 Writing questions on the Digital SAT will relate to punctuation and grammar. If you don’t know the SAT grammar rules, you may not be sure how to approach these questions.

If you just choose based on how the sentence sounds, you will probably end up with some wrong answers. That’s because the way we speak, and even the way we write in informal contexts such as social media and texting, doesn’t always follow the rules of written English. Something that “sounds right” can be incorrect, and something that “sounds wrong” can be correct. Here are some SAT grammar rules to use instead when you’re facing one of these questions.

Letter blocks spelling the word grammar

1. Subjects and verbs must agree.

Every sentence has a verb (an action word or a state of being, such as “reveal” or “were”) and a    subject for that verb (the one doing the action). Watch out for words between the subject and the verb that could be used to trick you.

Example: The teacher with the green shoes lives in my neighborhood.

The teacher lives in my neighborhood, not the shoes , so the subject is teacher . This word is singular, so the singular verb lives is used. Don’t be tricked by the plural noun shoes that comes right before the verb. It’s not the subject.

2. A verb must be in the correct tense based on clues in the text.

If the sentence is describing something that will happen, then you need a future tense verb. If the sentence refers to something that has already happened, then you need a past tense verb.

How do you know whether the sentence is describing a past, present, or future event? Look for clues, such as other verbs and references to time.

Example: I was eating a snack when my cousin called me.

Explanation: The verb called is in the past tense, and the word when suggests that the snack-eating happened at the same time, so the verb “to eat” needs to be in the past tense. Furthermore, was eating is more appropriate than other past tense verbs (such as ate or had eaten ) because the word when in this context means that the first event was in progress when the second one happened.

3. Pronouns need to agree with their antecedents.

If the antecedent is plural, then the pronoun referring back to it must also be plural. If the antecedent is singular, then the pronoun referring back to it must be singular.

A pronoun is a word such as it, she, or them that stands in for and refers back to a noun (called an antecedent).

Example: The Venus flytrap’s “jaws” only close when it senses contact from prey.

Explanation: The antecedent is The Venus flytrap , which is singular, so the singular pronoun it should be used—not the plural pronoun they .

4. Possessive pronouns and contractions need to be written correctly.

Apostrophes in pronouns represent contractions, so it’s means “it is” and they’re means “they are.” Its and their are possessive pronouns, meaning “belonging to it” and “belonging to them,” respectively.

You may be tested on the difference between its and it’s versus their and they’re (or other pronouns with apostrophes).

Example: The store opened its doors on January 1 st .

Explanation: The pronoun refers back to The store , which is singular, so a form of it and not a form of they should be used. Then, a possessive pronoun is needed because the phrase is referring to the doors of the store, so the correct spelling is its .

5. Plural and possessive nouns need to be properly punctuated.

To make a regular plural noun possessive, add an apostrophe after the plural - s or - es. To make an irregular plural noun possessive, add an apostrophe + - s.

Most nouns add an - s or - es to become plural. Some, such as children or people, are irregular plurals and don’t end in - s. To make a singular noun possessive, add an apostrophe + - s.

Example: Put the students’ projects on top of the lockers.

Explanation: The sentence refers to the projects of multiple students, so keep the word students plural and add the apostrophe after to show that the projects belong to them. The word projects is plural, so it ends with - s, but nothing belongs to the projects, so that word doesn’t need an apostrophe. 

6. With modifiers, the person or thing being modified needs to come as close as possible to the modifier.

Look for a phrase at the beginning of a sentence that is followed by a comma.

Example: Using the results of the study, the research team was able to come to a conclusion.

Explanation: The research team used the results of the study, so that’s what should come after the comma. If the word conclusion had come after the comma, the sentence would be incorrect because a conclusion can’t use something.

Try looking out for these SAT grammar rules next time you practice. If you can apply what you’ve learned to identify when each rule is being tested, you should be able to get the questions right, whether they “sound” correct or not!