Rule 1: Periods = Semicolons (. = ;)

On the Digital SAT, a period and a semicolon are grammatically interchangeable. Both separate two complete, standalone sentences (independent clauses). If you see an answer choice with a period and another with a semicolon in the exact same spot, you can eliminate both.

Example: TTA is a great prep tool; it has thousands of questions.
Example: TTA is a great prep tool. It has thousands of questions.

Rule 2: Colons = Dashes (: = –)

Colons and dashes are often functionally identical on the SAT. They have two primary uses:

1. Before a List: Must follow a complete sentence.
   Correct: The guide covers four topics: math, reading, writing, and grammar.
2. Before an Explanation: The second clause explains or defines the first.
   Correct: The channel was famous: students flocked to its advice.

A common trap is using a colon after an incomplete thought (for example, "The topics include: ..."). This is always incorrect.

Rule 3: Joining Sentences with Comma + FANBOYS

To connect two independent clauses, use a comma followed by a coordinating conjunction (For, And, Nor, But, Or, Yet, So). The structure is: Independent Clause, FANBOYS Independent Clause.

Example: He won the science fair, so he started a company to help others.

Rule 4: Commas After Introductory Dependent Clauses

A dependent clause cannot stand on its own as a sentence. It often starts with a word like although, because, when, since, or similar. When one of these clauses starts a sentence, it must be followed by a comma.

Example: Because London is a very old city, it has buildings from many different eras.

Rule 5: Non-Essential Information

Some phrases provide extra detail but are not grammatically necessary. This non-essential information must be set off from the sentence with a pair of commas or a pair of dashes. You cannot mix and match.

Example: London, which is a very old city, has some extremely modern parts.

Rule 6: Transition Words

These questions ask you to choose the logical transition between ideas. You must read the sentences before and after the blank to understand the relationship. The main categories are:

• Continuers: In addition, moreover, for example.
• Cause-and-Effect: Therefore, consequently, thus.
• Contradictors: However, nevertheless, in contrast.

Rule 7: Other Common Comma Uses

• Separating Items in a List: He ordered carrots, apples, and bananas.
• Separating Reversible Adjectives: She is a cool, smart individual. (You can say "smart, cool," so the comma is needed.)

Rule 8: Apostrophes (Possessive vs. Contraction)

This is a major topic on the SAT. The rule is simple: contractions use an apostrophe (it's = it is), while possessive pronouns do not (its, their, your, whose).

• It's vs. Its: It's black. vs. Its fur is black.
• They're vs. Their vs. There: They're short. vs. Their backpack. vs. There are mice.
• Who's vs. Whose: Who's at the door? vs. Whose backpack?
• Plural Possessives: For plural nouns ending in "s," the apostrophe goes after the s (the cells' walls). For singular nouns ending in "s," it is 's (the dress's color).

Rule 9: Subject-Verb Agreement (Sound It Out)

A compound subject (two nouns joined by "and") is plural and requires a plural verb. If you are unsure, sounding it out can help.

Correct: The bark and silhouette of the tree distinguish it. (NOT "distinguishes")

Rule 10: Verb Tense Consistency

Verb tenses should remain consistent unless there is a clear time shift. For actions that started in the past and continue, use the "have been" form, especially with words like "for" and "since."

Correct: London and Paris have been tourist attractions for hundreds of years.

Rule 11: Active vs. Passive Voice

The SAT prefers the direct and clear active voice. If multiple choices are grammatically correct, pick the most concise and active one.

Passive (Wordy): ...concerns are had by them...
Active (Better): ...they are concerned...

Rule 12: Parallel Structure

Items in a list must be in the same grammatical form (for example, noun, noun, noun or -ING, -ING, -ING).

Correct: He has worked to publish, communicate, and present his research.

Rule 13: Dangling Modifiers

An introductory phrase must describe the subject that immediately follows the comma.

Incorrect: Born in 2004, computers were his hobby. (This implies the computers were born in 2004.)

Correct: Born in 2004, he made computers his hobby.

Rule 14: Faulty Comparisons

You must compare like things. You cannot compare a person to an object.

Incorrect: ...videos of Rishab are just as well-known as Bob...
Correct: ...videos of Rishab are just as well-known as the TikToks of Bob.

Rule 15: Quantity Words

Use certain words for countable items and others for non-countable items.

• For PLURAL (Countable): Number, Many, Fewer (for example, fewer subscribers).
• For SINGULAR (Non-Countable): Amount, Much, Less (for example, less water).

The College Board designs the Digital SAT Writing and Language section to test your command of standard English conventions. According to the official SAT specifications, grammar questions make up a significant portion of the module. Mastering these 15 rules directly improves your score. The test uses a consistent format across all administrations, so the same patterns appear in every exam. When you practice with Bluebook official practice tests, you see these rules applied in the exact same way they appear on test day. This consistency means that focused study on these rules yields predictable score gains.

Many students lose points on grammar questions because they rely on what "sounds right" rather than applying the rules. The SAT includes trap answer choices that sound natural but violate a specific rule. For example, a sentence might read "The group of students were excited" which sounds acceptable in casual speech but is incorrect because the subject "group" is singular. Another frequent error involves confusing possessive and contraction forms. Students often choose "it's" when the possessive "its" is required. The best way to avoid these traps is to identify the rule being tested before looking at the answer choices. The Test Advantage recommends reading the sentence without the underlined portion first to spot the grammatical structure.

To internalize these grammar rules, use a structured practice approach. Start by reviewing each rule with a clear example. Then complete 10 to 15 practice questions that target that specific rule. After each question, write down why the correct answer works and why each wrong answer fails. This process builds pattern recognition. The Test Advantage platform provides Targeted Practice for each grammar rule, allowing you to isolate your weak areas. As you improve, mix rules together in practice sets to simulate the actual test. Track your accuracy over time and revisit rules where you score below 80 percent. Consistent practice with realistic Digital SAT questions is the most effective way to raise your score.

For a one-page reference while you review, see the full SAT grammar cheat sheet for 2026, which covers semicolons, the four jobs of a comma, colons, dashes, and subject-verb agreement.