SAT Grammar Rules

What You Need to Know (and Why It Matters)

On the SAT Writing & Language questions, “grammar” is really a set of predictable rules about sentence structure, punctuation, agreement, and clarity. Most questions have one answer that is grammatically correct and most concise/clear.

Core idea: Choose the option that preserves the sentence’s intended meaning while following standard written English. When in doubt, prioritize:
1) Grammar correctness (hard rules), then
2) Clarity and concision (style rules), then
3) Consistency (tense, tone, point of view).

Warning: Many wrong answers are tempting because they “sound right.” On the SAT, you win by checking structure (clause boundaries, subject/verb, pronoun reference), not by ear.

Step-by-Step Breakdown (How to Attack Any Grammar Question)

1) Read the whole sentence (or at least the full thought). Identify what the sentence is trying to say.
2) Spot what’s changing in the answer choices.

• If only punctuation changes → it’s a punctuation/clause question.
• If verbs change → tense/agreement.
• If pronouns change → pronoun case/clarity.
• If wording changes → concision/idiom/parallelism.
  3) Identify the core structure:
• Find the main subject and main verb.
• Mark independent clauses (can stand alone) vs dependent clauses.
  4) Apply the relevant rule (don’t guess).
  5) Do a quick meaning check:
• No unintended change in meaning.
• No ambiguity (especially pronouns).
• Most concise choice that is still clear and grammatical.

Mini worked “process” example

Sentence: “The committee reviewed the proposal, it recommended changes.”

• Two complete thoughts (independent clauses) are joined by a comma → comma splice.
• Fix options you should look for:
  • Semicolon: “…proposal; it recommended…”
  • Comma + FANBOYS: “…proposal, and it recommended…”
  • Period: “…proposal. It recommended…”
  • Subordination: “…proposal, recommending changes.” (only if meaning fits)

Key Formulas, Rules & Facts

Sentence boundaries (the highest-yield SAT grammar area)

FANBOYS coordinating conjunctions: for, and, nor, but, or, yet, so.

• Pattern: Independent clause, FANBOYS independent clause.

Commas (rules that show up constantly)

Essential vs nonessential is a meaning question: Does the sentence need that phrase to know which one?

“That” vs “which” (SAT-style)

• That introduces essential (restrictive) information → no comma.
  • “Books that have illustrations appeal to children.”
• Which often introduces nonessential info → comma before which.
  • “The book, which was published in 1922, became a classic.”

Apostrophes & possession

Subject–verb agreement (ignore distractions)

• Verb must match the true subject, not words in between.
  • “The bouquet of roses is…” (subject = bouquet)
• Either/Neither/Each/Everyone/Anyone are typically singular.
  • “Each of the students has a locker.”
• Collective nouns (team, committee) are usually singular on the SAT.
  • “The team is practicing.”

Verb tense & consistency

Pronouns (case, agreement, clarity)

Modifiers (placement matters)

• A modifier must be placed next to what it modifies.
  • Wrong: “Walking down the street, the trees were beautiful.”
  • Right: “Walking down the street, I thought the trees were beautiful.”
• Dangling modifiers lack a clear target.
• Misplaced modifiers attach to the wrong noun.

Parallelism (lists and comparisons)

• Items in a list must match grammatical form:
  • “She likes running, swimming, and biking.”
  • Not: “running, to swim, and biking.”
• Comparisons must be logical and parallel:
  • “The earnings of Company A are higher than those of Company B.”

Comparisons & idiom-style correctness

• Use than for comparisons; avoid illogical comparisons.
• Watch fewer vs less:
  • Fewer = countable (fewer cars)
  • Less = uncountable (less traffic)

Concision & redundancy (style rules SAT loves)

• Prefer the shortest choice that keeps meaning and grammar.
• Cut common redundancies:
  • “Advance planning” → “planning”
  • “In order to” → “to”
  • “Due to the fact that” → “because”
• Avoid wordy “there is/there are” constructions if an active, direct option exists.

Transitions & logical connectors

• Choose transitions based on logic, not vibe:
  • However/Nevertheless = contrast
  • Therefore/Thus = result
  • Moreover/Furthermore = add
  • For example/For instance = illustration
• The best transition matches the relationship between sentences.

Examples & Applications

Example 1: Comma vs semicolon vs colon

“Maria wanted one thing from the meeting: clarity.”

• Correct because colon follows a complete clause (“Maria wanted one thing from the meeting”) and introduces an explanation.
• Wrong pattern to avoid: “Maria wanted one thing: from the meeting clarity.” (colon can’t split subject-verb or break the clause incorrectly)

Example 2: Essential vs nonessential

“The students who studied the guide passed the quiz.”

• No commas because “who studied the guide” specifies which students.
  “The students, who studied the guide, passed the quiz.”
• With commas, it implies all the students studied the guide (extra info). Meaning changes.

Example 3: Subject–verb agreement with a prepositional phrase

“The cost of the new regulations is rising.”

• Subject = cost (singular), not “regulations.”

Example 4: Modifier placement

Wrong: “She served sandwiches to the children on paper plates.”

• As written, children are on plates.
  Better: “She served the children sandwiches on paper plates.”
• Modifier is placed next to what it describes (sandwiches/serving setup).

Common Mistakes & Traps

1) Comma splice

• What you do: Join two complete sentences with just a comma.
• Why wrong: A comma alone can’t join two independent clauses.
• Fix: ; or . or , + FANBOYS or restructure.

2) Forgetting to test independence

• What you do: Use a semicolon/colon when one side isn’t a complete sentence.
• Why wrong: Semicolon requires independent clauses; colon requires an independent clause before it.
• Fix: Read each side as a standalone sentence.

3) Mislabeling essential vs nonessential

• What you do: Add commas around a clause that’s needed to identify the noun.
• Why wrong: Commas signal “extra” info; meaning changes.
• Fix: Ask: “Do I need this to know which one?”

4) Agreement errors caused by “interruptors”

• What you do: Match verb to the closest noun (“roses are” instead of “bouquet is”).
• Why wrong: Verb agrees with the subject, not a noun in a prepositional phrase.
• Fix: Cross out prepositional phrases (“of…, with…, along with…”), then match.

5) Pronoun ambiguity

• What you do: Use “it/they/this” when multiple nouns could be the antecedent.
• Why wrong: Unclear meaning.
• Fix: Replace pronoun with the noun mentally; ensure only one possible referent.

6) Dangling modifiers

• What you do: Start with an -ing phrase but the next noun can’t do that action.
• Why wrong: The modifier has no valid target.
• Fix: Put the actor immediately after the comma.

7) Nonparallel lists

• What you do: Mix verb forms or structures in a list.
• Why wrong: SAT prefers consistent grammar patterns.
• Fix: Line up list items; make them match (noun/noun/noun or -ing/-ing/-ing).

8) Choosing wordier answers “to be safe”

• What you do: Pick the longest option because it sounds formal.
• Why wrong: SAT rewards concise, precise wording.
• Fix: If two answers are grammatical and equivalent in meaning, choose the shorter.

Memory Aids & Quick Tricks

Quick Review Checklist

• Identify independent vs dependent clauses before picking punctuation.
• Never join two independent clauses with a comma alone.
• Semicolon: both sides must be complete sentences.
• Colon: left side must be a complete sentence; right side explains/lists.
• Use commas for introductory elements and nonessential info; skip commas for essential info.
• Ensure subject–verb agreement with the true subject (ignore “of…, with…” phrases).
• Keep verb tense consistent and logical.
• Pronouns must be clear, agree in number, and use correct case (I/me, who/whom).
• Fix dangling/misplaced modifiers by putting the actor right after the modifier.
• Enforce parallel structure in lists and comparisons.
• Prefer the most concise option that preserves meaning.

You don’t need perfect “ear” for this—run the structure checks and you’ll rack up points fast.