The 12 Essential Digital SAT Grammar Rules (2026)
Over 40% of the Digital SAT Reading & Writing questions test predictable grammatical conventions and rhetorical synthesis. Learn the rules College Board tests on every single exam date.
Quick Jump to High-Yield Rules
Period = Semicolon = Comma + FANBOYS
An independent clause has both a subject and a conjugated verb and can stand alone as a sentence. Two independent clauses cannot be glued together with just a comma (this is a comma splice, the #1 grammar error tested on the SAT).
The satellite reached orbit, it transmitted high-resolution telemetry back to Earth.
The satellite reached orbit; it transmitted high-resolution telemetry back to Earth.
Citadel Test Hack: If two multiple choice options are identical except one uses a period and the other uses a semicolon, eliminate both immediately! On the SAT, a semicolon and a period are grammatically interchangeable.
The FANBOYS Comma Rule
Use a comma before a coordinating conjunction (For, And, Nor, But, Or, Yet, So) only when it connects two full independent clauses.
Do NOT use a comma if the second clause lacks an explicit subject:
Non-Essential Clauses: Match Your Bookends
Non-essential information (appositives or parenthetical phrases) can be removed from the sentence without breaking grammatical integrity. They must be enclosed symmetrically: either with two commas, two dashes, or parentheses.
Never mix a comma with an em-dash. If a clause begins with an em-dash (\(—\)), it must close with an em-dash before the main verb.
Dangling Modifiers: Who Is Doing the Action?
When a sentence begins with an introductory descriptive phrase (especially ending in -ing or -ed), the noun immediately following the comma must be the entity actually performing that action.
Hiking through the dense Redwood forest, the towering trees astonished Sarah.
(The trees weren't hiking!)Hiking through the dense Redwood forest, Sarah was astonished by the towering trees.
Ignore the Prepositional Distractor
The SAT loves to insert long prepositional phrases (starting with of, in, by, with, for, between) between the subject and the verb to fool you into matching the verb to the wrong noun.
Example: The preservation of ancient Roman mosaics and marble statues requires (not require) specialized dehumidification systems.
Cross out "of ancient Roman mosaics and marble statues". The subject is singular: preservation → requires.
The 4-Step Bullet Point Method
On "While researching a topic, a student has taken the following notes..." questions, do not read the bullet points first! That wastes 45 seconds.
Categorize Transitions into 3 Buckets
Every transition question falls into one of three logical categories:
However, Nevertheless, Conversely, Despite this, In contrast
Therefore, Consequently, As a result, Thus, Accordingly
Furthermore, Moreover, In addition, Specifically, For example
Put Grammar Rules to the Test
Test Citadel's adaptive Reading & Writing modules test all 12 conventions with zero duplicate questions and instant Socratic hints.