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Reading & Writing12 min readUpdated August 2026

Digital SAT Grammar Rules: The Complete Standard English Conventions Guide

The comprehensive guide to all Standard English Conventions tested on the Digital SAT: punctuation hierarchy, modifier placement, verb tense, and parallel structure.

Sarah Jenkins
Written by
Sarah Jenkins
MA in English Literature (Oxford University), Perfect 800 Reading & Writing
Medically & Academically Reviewed by: Dr. Kemi AdebayoChief Psychometrician & Head of SAT Curriculum

Standard English Conventions account for approximately 26% of all Reading & Writing questions (11 to 15 questions per test).

Unlike literary analysis or vocabulary memorization, grammar questions follow deterministic, binary mathematical rules. Once you master the rules, you can answer every grammar question with 100% accuracy.

1. The 4 Punctuation Tiers on the SAT

Every punctuation question tests clause boundaries. There are only two types of clauses:

  • Independent Clause (IC): Contains a subject and a verb and expresses a complete thought. Can stand alone as a complete sentence.
  • Dependent Clause (DC): Contains a subject and verb but begins with a subordinating conjunction (e.g., Although, Because, While, Since) or relative pronoun (e.g., which, that, who). Cannot stand alone.

2. Semicolons & Periods: Independent Clauses

On the SAT, a period (.) and a semicolon (;) perform identical grammatical functions: they separate two independent clauses.

[Independent Clause] ; [Independent Clause]

[Independent Clause] . [Independent Clause]

💡 Expert Strategy Tip
If two answer choices are identical except that one uses a semicolon and the other uses a period (with identical wording), both choices are automatically incorrect because they perform the exact same function.

3. Colons & Single Dashes: The Announcement Rule

A colon (:) or single em dash (—) introduces an explanation, list, definition, or dramatic conclusion.

The non-negotiable rule on the SAT:

  • Before the colon: Must be a 100% complete Independent Clause.
  • After the colon: Can be an Independent Clause, a Dependent Clause, a list, or a single word.

Correct Example:

The archaeologist discovered a rare artifact: a Bronze Age ceremonial dagger. (Independent clause before colon).

Incorrect Example:

The artifacts discovered included: daggers, coins, and pottery. (Incomplete clause before colon).

4. Comma Splices & FANBOYS Coordination

A comma splice occurs when two independent clauses are joined by a comma alone without a coordinating conjunction. This is always grammatically incorrect on the SAT.

To join two independent clauses with a comma, you must include a FANBOYS conjunction (For, And, Nor, But, Or, Yet, So):

[Independent Clause] , and [Independent Clause]

5. Dangling & Misplaced Modifiers

When a sentence opens with an introductory modifying phrase (a phrase describing an action without its own subject), the noun being modified must immediately follow the comma.

  • Incorrect: Walking through the museum, ancient dinosaur fossils caught the student's attention. (Implies the fossils were walking).
  • Correct: Walking through the museum, the student noticed ancient dinosaur fossils. (The student was walking).

6. Apostrophes & Possessive Pronouns

Pronoun / NounMeaningExample
It'sContraction for It is or It hasIt's raining outside.
ItsSingular Possessive pronounThe camera lost its lens cap.
Its'DOES NOT EXISTNever correct on the SAT.
They'reContraction for They areThey're studying in the library.
TheirPlural Possessive pronounThe students submitted their exams.
ThereLocation or existential pronounPut the book over there.
Student'sSingular Possessive (one student)The student's desk.
Students'Plural Possessive (multiple students)The students' desks.

Practice these rules on SAT.ng Standard English Conventions Drills.

Recommended Next Steps & Practice

Practice Questions on this Topic

Frequently Asked Questions

How many grammar questions are on the Digital SAT?

There are approximately 11 to 15 Standard English Conventions questions across the two Reading & Writing modules.

Is the Oxford Comma tested on the SAT?

The SAT is consistent in its usage, but never creates a question where the sole deciding difference between two choices is the Oxford Comma.