The digital SAT tests grammar in Standard English Conventions questions: about 26% of the Reading and Writing section, or 11 to 15 of its 54 questions. They cover punctuation between and within sentences, and agreement, tense, possessives and modifiers. Below are the 18 rules behind those questions (plus transitions and concise wording, tested in Expression of Ideas), each with examples and 2 practice questions. Answer all 36 for a score that shows which rules to review.
| Rule | What to check |
|---|---|
| 1. Subject-verb agreement | Find the real subject; ignore phrases between it and the verb. |
| 2. Verb tense | Match the tense of the other verbs and any time words. |
| 3. Pronoun agreement | Singular noun, singular pronoun: a company is "it", not "they". |
| 4. Its/it's, their/they're | Read the apostrophe as "it is" or "they are"; if that doesn't fit, drop it. |
| 5. Plurals and possessives | Apostrophe only for ownership: teacher's (one), teachers' (many), children's. |
| 6. Modifiers | The noun right after the comma must be the one doing the action. |
| 7. Semicolons and periods | Both need a complete sentence on each side. |
| 8. Colons and dashes | A complete sentence must come before them. |
| 9. Commas with FANBOYS | Two complete sentences: comma + for, and, nor, but, or, yet, so. |
| 10. Dependent clauses | Comma after an opening because, although or when clause. |
| 11. Transitions | Name the relationship first: contrast, cause, addition, example. |
| 12. Non-essential information | A matching pair: two commas, two dashes or two parentheses. |
| 13. Names and titles | No commas if the name is needed to know who; commas if it's extra. |
| 14. Parallel structure | Items in a list or pair share the same form. |
| 15. Comparisons | Compare like with like; than (not then); fewer for things you can count. |
| 16. Question marks | Only for direct questions. |
| 17. Word choice | Pick the word with the exact meaning: affect/effect, allusion/illusion. |
| 18. Shorter is better | If two choices are correct and mean the same, take the shorter. |
The Digital SAT Reading and Writing section tests grammar knowledge through 'Standard English Conventions' questions. These questions typically test a variety of grammar rules, including subject-verb agreement, verb tense consistency, pronoun-antecedent agreement, and more.
Understanding these rules is crucial not only for this section but also for overall reading comprehension and clear communication. This guide will explain 18 key SAT grammar rules tested on the SAT, how they're tested, and give examples and practice questions to help you succeed.
Rule: Subjects and verbs must agree in number. Singular subjects take singular verbs, and plural subjects take plural verbs. This rule is often tested by separating the subject and verb with phrases.
How it's tested: The SAT will try to trick you with phrases or clauses between the subject and verb, making it harder to identify the true subject.
Examples:
Correct: The doctor with the white coat works at the local hospital.
This is correct because the singular subject "doctor" agrees with the singular verb "works". The phrase "with the white coat" doesn't affect the agreement.
Incorrect: The players on the team wants to win the championship.
This is incorrect because the plural subject "players" doesn't agree with the singular verb "wants". Don't be fooled by the singular "team" - "players" is the subject.
Correct: The players on the team want to win the championship.
This is correct because the plural subject "players" agrees with the plural verb "want".
The teacher, along with several other professors, _____ highly qualified.
Each of the players _____ scored a goal.
Rule: Verb tenses should be consistent within a sentence and paragraph. Shifts in tense should only occur when there is a logical reason, such as when describing events at different times.
How it's tested: The SAT will present sentences or paragraphs with unnecessary tense shifts, requiring you to choose the consistent verb form. Clues within the sentence and surrounding sentences, such as time references, should indicate the correct tense.
Examples:
Incorrect: Yesterday, Sarah bought a ticket and flies to Paris.
This is incorrect because it illogically shifts from past tense "bought" to present tense "flies" when describing events that happened yesterday.
Correct: Yesterday, Sarah bought a ticket and flew to Paris.
This is correct because both verbs "bought" and "flew" are in the past tense, matching the time reference "yesterday".
Incorrect: Michael works at a hospital. He liked helping patients.
This is incorrect because it shifts from present tense "works" to past tense "liked" without any logical reason.
Correct: Michael works at a hospital. He likes helping patients.
This is correct because both verbs "works" and "likes" are in the present tense, maintaining consistency.
The artist _____ inspired by nature when she creates her paintings.
By the time she arrived, the show _____.
Rule: Pronouns must agree with their antecedents (the nouns they refer to) in number and gender. Singular antecedents take singular pronouns; plural antecedents take plural pronouns.
How it's tested: The SAT may use sentences where a pronoun does not match the number or gender of its antecedent.
Examples:
Incorrect: The museum reopened after renovations, and they now offer free tours.
This is incorrect because the singular antecedent "museum" is paired with the plural pronoun "they".
Correct: The museum reopened after renovations, and it now offers free tours.
This is correct because the singular pronoun "it" agrees with the singular antecedent "museum".
Incorrect: The company updated their logo.
This is incorrect because the plural pronoun "their" doesn't agree with the singular antecedent "company". On the SAT, a company, team or committee is "it".
Correct: The company updated its logo.
This is correct because the singular pronoun "its" agrees with the singular antecedent "company".
The students finished _____ projects early.
Each of the three cities has _____ own transit system.
Rule: Understand the difference between possessive pronouns (its, their) and contractions (it's, they're). Apostrophes in pronouns signify contractions, meaning "it is" or "they are". Possessive pronouns show ownership.
How it's tested: The SAT frequently tests the difference between its/it's, and their/they're, requiring you to choose the correct form based on the sentence.
Examples:
Incorrect: The company launched it's new product in March.
This is incorrect because "it's" is a contraction meaning "it is". The sentence needs the possessive pronoun "its" to show ownership.
Correct: The company launched its new product in March.
This is correct because "its" is the possessive pronoun showing the product belongs to the company.
Incorrect: Rome and Venice are beautiful Italian cities, and their famous for their architecture.
This is incorrect because "their" is a possessive pronoun, but the sentence needs the contraction "they're" meaning "they are".
Correct: Rome and Venice are beautiful Italian cities, and they're famous for their architecture.
This is correct because "they're" is the contraction of "they are", which is what the sentence requires.
The dog wagged _____ tail excitedly.
_____ going to the park later this afternoon.
Rule: Regular plural nouns are made by adding -s or -es. To make a regular plural noun possessive, add an apostrophe after the plural -s or -es. Irregular plural nouns add an apostrophe + -s. Singular nouns are made possessive by adding an apostrophe + -s.
How it's tested: The SAT tests the correct placement of apostrophes with both plural and possessive nouns, in addition to testing whether a noun should be plural or singular.
Examples:
Correct: Store the teachers' books in the supply closet.
This is correct because it shows possession by multiple teachers (plural possessive) with the apostrophe after the plural -s.
Correct: Modern architecture is defined by the architect's use of clean lines.
This is correct because it shows possession by a single architect (singular possessive) with apostrophe + s.
Incorrect: Each evening, several deer's wandered into the garden, eating plants.
This is incorrect because "deer" is already plural and doesn't need an apostrophe since it's not showing possession.
Correct: Each evening, several deer wandered into the garden, eating plants.
This is correct because "deer" is both singular and plural - no change is needed to make it plural.
The _____ toys were scattered all over the room.
The _____ meows could be heard from across the street.
Rule: The person or thing being modified needs to be as close as possible to the modifier. When a modifying phrase begins a sentence, the noun being modified must immediately follow the comma.
How it's tested: The SAT often presents sentences with misplaced or dangling modifiers, where the modified element isn't clear or is incorrectly placed.
Examples:
Correct: After analyzing the data, the scientists reached their final conclusion.
This is correct because "the scientists" (who did the analyzing) immediately follows the modifying phrase.
Incorrect: Growing up in the port town of Le Havre, paintings were what Claude Monet excelled at creating.
This is incorrect because the modifier "Growing up in the port town of Le Havre" is describing paintings, which cannot grow up anywhere.
Correct: Growing up in the port town of Le Havre, Claude Monet excelled at creating paintings.
This is correct because the person who grew up in Le Havre (Claude Monet) immediately follows the modifying phrase.
Incorrect: An aspiring musician, Michael's dream is to perform at Carnegie Hall next spring.
This is incorrect because "Michael's dream" cannot be an aspiring musician - Michael is the aspiring musician.
Correct: An aspiring musician, Michael dreams of performing at Carnegie Hall next spring.
This is correct because Michael (the aspiring musician) immediately follows the modifying phrase.
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Rule: Semicolons and periods are essentially interchangeable on the SAT. They are used to separate two complete sentences (independent clauses).
How it's tested: The SAT may ask you to choose between a semicolon or a period, or to identify whether a semicolon is correctly used to separate two complete sentences.
Examples:
Correct: The museum is very popular. It attracts millions of visitors each year.
Correct: The museum is very popular; it has fascinating exhibits.
Correct: The museum is very popular; however, it needs renovation.
Incorrect: Because Michael loved to create art; he became a painter.
This is incorrect because "Because Michael loved to create art" is not a complete sentence.
Correct: Michael loved to create art; he became a painter.
This is correct because both parts are complete sentences that can stand alone.
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Rule: Colons and dashes introduce lists, explanations, or examples. They must follow a complete sentence (independent clause).
How it's tested: The SAT tests the correct use of colons and dashes, particularly if they are preceded by complete sentences, as well as if they are followed by lists and explanations.
Examples:
Correct: The basketball team needs three key qualities: speed, strength, and teamwork.
Incorrect: Sarah practices several types of dance like: ballet, jazz, tap, and modern.
This is incorrect because "like" and a colon should not be used together - use one or the other.
Correct: Sarah practices several types of dance: ballet, jazz, tap, and modern.
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Rule: Use a comma before a coordinating conjunction (for, and, nor, but, or, yet, so - FANBOYS) when it joins two independent clauses.
How it's tested: The SAT may present comma splices (two independent clauses joined only by a comma) or incorrectly omit commas with FANBOYS.
Examples:
Correct: The movie was very long, but the story kept me engaged.
Incorrect: The movie was very long, the story kept me engaged.
This is incorrect because it's a comma splice - two independent clauses joined only by a comma without a conjunction.
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Rule: When a dependent clause (a clause that cannot stand alone as a sentence) comes before an independent clause, a comma is required.
Examples:
Correct: Because the test was very challenging, many students studied for extra hours.
Incorrect: Because the test was very challenging many students studied for extra hours.
This is incorrect because it's missing a comma after the introductory dependent clause.
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Rule: Transitional words and phrases connect ideas and indicate relationships, like continuation, contrast, or cause-and-effect.
How it's tested: The SAT will ask you to choose the correct transitional word or phrase to create the most logical connection between sentences.
Examples:
Correct: The experiment was expected to take a week. However, the results were ready in two days.
This is correct because "However" properly signals the contrast between what was expected and what happened.
Incorrect: The weather was beautiful today. Therefore, bananas are a good source of potassium.
This is incorrect because "Therefore" implies a cause-and-effect relationship, but there is no logical connection between the weather and bananas.
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Rule: Non-essential information (phrases or clauses) can be removed from a sentence without changing its core meaning. It should be set off by commas, dashes, or parentheses.
How it's tested: The SAT tests your ability to correctly punctuate non-essential information using commas, dashes, or parentheses, and to not mix punctuation types.
Examples:
Correct: Paris, which is the capital of France, attracts millions of tourists.
Correct: Notre Dame Cathedral—which dates back to medieval times— draws many visitors.
Incorrect: The Seine River—which flows through Paris, provides scenic views.
This is incorrect because it mixes two different types of punctuation (em dash and comma) to set off the non-essential information.
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Rule: Use commas to set off names or titles when they are non-essential (add extra information but are not needed for the sentence to make sense). Essential names/titles should not have commas.
Examples:
Correct: The novelist Toni Morrison won the Nobel Prize in Literature in 1993.
This is correct because "Toni Morrison" is essential information: without it, we don't know which novelist the sentence means.
Correct: The first Black woman to win the Nobel Prize in Literature, Toni Morrison, received it in 1993.
This is correct because "Toni Morrison" is non-essential here: the description before it already identifies exactly one person.
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Rule: When listing items or pairing items, use consistent grammatical structure (nouns with nouns, verbs with verbs, etc.). This applies to lists and word pairs (either/or, not only/but also).
Examples:
Correct: The research team has gathered data from scientists, engineers, and technicians to study climate change patterns.
Incorrect: The research team has gathered data from scientists, engineers, and working as technicians to study climate change patterns.
This is incorrect because "working as technicians" breaks the parallel structure by using a verb phrase instead of a noun.
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Rule: Comparisons must be made between equivalent items (people to people, things to things). Use "than" not "then" to form comparisons. "Number", "many", and "fewer" go with things you can count (students, books). "Amount", "much", and "less" go with things you can't count (water, time).
Examples:
Incorrect: Though the music of composer Mozart is just as influential as Beethoven, Mozart died at a much younger age.
This is incorrect because it compares "the music" to "Beethoven" directly, rather than comparing equivalent items (music to music).
Correct: Though the music of composer Mozart is just as influential as the music of Beethoven, Mozart died at a much younger age.
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Rule: Question marks are used for direct questions. Indirect questions, which are integrated into a sentence, do not use question marks and end in periods.
Examples:
Correct: The research aimed to answer one central question: what impact does ocean pollution have on coral reef ecosystems?
Incorrect: The research aimed to answer what impact ocean pollution has on coral reef ecosystems?
This is incorrect because it uses a question mark at the end of an indirect question. Indirect questions should end with a period.
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Rule: Select words that have the correct meaning and register (formal vs. informal). Pay attention to commonly confused words such as affect/effect, than/then, allusion/illusion, elicit/illicit, and anyway/anyways.
Examples:
Correct: The effect of excessive screen time on children's sleep patterns has been well documented.
Incorrect: The affect of excessive screen time on children's sleep patterns has been well documented.
This is incorrect because "affect" is being used as a noun when it should be "effect" since we're referring to the result/impact.
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Rule: When multiple answers are grammatically correct and have the same meaning, choose the shortest answer.
Examples:
Correct: The discovery of penicillin revolutionized modern medicine.
Incorrect: The discovery of penicillin brought about and created a revolutionary change and transformation in the field of modern medicine.
This is incorrect because it uses redundant phrases that add unnecessary length without adding meaning.
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Answer the practice questions under each rule and your score shows up here, with the rules to review.
Last verified October 21, 2026.