Master the Digital SAT: Every Grammar Rule You Need in 15 Minutes

The Writing and Language section of the Digital SAT can be one of the most intimidating parts of the test. With dozens of seemingly complex grammar rules, it's easy to feel overwhelmed. But what if you could master the most important concepts quickly and efficiently? This guide, based on expert insights, provides a comprehensive breakdown of the essential grammar rules that show up time and again on the SAT.

Part 1: Sentence Structure Rules

Rule 1: Periods = Semicolons (. = ;)

On the Digital SAT, a period and a semicolon are grammatically interchangeable. Both are used to 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 of them.

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 (: = –)

Similar to the first rule, 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 (e.g., "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 and often starts with a word like although, because, when, since, etc. 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.

Part 2: Punctuation and Word Choice Rules

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's 's (the dress's color).

Part 3: Sentence Clarity and Logic Rules

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're 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 (e.g., 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. (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 (e.g., fewer subscribers).
• For SINGULAR (Non-Countable): Amount, Much, Less (e.g., less water).

The TTA Pro Practice Strategy

How to Apply These Rules for Maximum Improvement

• Practice with Realistic Tests: The best way to improve is through consistent, targeted practice. Using a platform with thousands of questions that mirror the Digital SAT format is essential for preparing for the adaptive nature of the test.
• Warm Up on Test Day: The Writing & Language section is one of an SAT module's first parts. To warm up your brain, read some articles or passages aloud (or in your head) on the way to the test center. This gets your "inner voice" ready for the rhythm of the test.
• Take Full-Length Diagnostic Tests: Use a tool like The Test Advantage to take full, timed practice exams. This alleviates test anxiety by familiarizing you with the format, timing, and nuances of the real exam.

Conclusion: Grammar is About Patterns

Mastering SAT grammar doesn't require memorizing an entire textbook. By focusing on these 15 core rules and implementing a smart practice strategy, you can build the skills and confidence to excel on the Writing & Language section.

To put these rules into practice on the most realistic Digital SAT questions available, check out our plans.

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