ACT English Rule Sheet
What You Need to Know
ACT English tests standard written English and rhetorical skills in context. Most questions are really about a small set of repeatable rules: punctuation, sentence structure, agreement, modifiers, pronouns, verb tense/voice, and concise, logical writing.
Two big categories of questions:
- Usage/Mechanics (Grammar & Punctuation): There is usually a right answer by rule.
- Rhetorical Skills (Style/Organization): You choose what is most clear, relevant, logical, and consistent with the passage’s purpose.
Critical mindset: Don’t pick what “sounds right.” Prove it with a rule or with the passage’s meaning.
Core rule principle: Punctuation is structural. It shows how ideas connect (independent vs dependent clauses, essential vs nonessential information, lists, interruptions).
Step-by-Step Breakdown
Use this process for almost every ACT English question:
Read enough context
- At least the full sentence; often the sentence before/after for transitions and pronouns.
Identify the question type
- Grammar/punctuation: look for commas, semicolons, colons, dashes, verb forms, pronouns.
- Style: look for wordiness, redundancy, vague wording.
- Organization: “best place,” “best transition,” “add/delete,” “conclusion,” “introduction.”
If it’s punctuation, label the pieces
- Independent clause (IC): can stand alone.
- Dependent clause (DC): cannot stand alone.
- Check whether the punctuation choice correctly joins/separates those structures.
For grammar, do a quick “core sentence” test
- Cross out prepositional phrases and interruptions to find subject → verb.
- Example core: “The collection of rare coins is valuable.” (subject = collection)
For style, choose the clearest + shortest that keeps meaning
- Prefer active voice, specific words, and no redundancy.
- Don’t delete information the sentence needs.
For rhetorical questions, match the author’s goal
- Is the passage informative, persuasive, narrative, humorous, formal?
- Pick transitions/details that fit the tone and purpose.
Re-read the edited sentence
- Make sure it’s grammatical, clear, and logical in context.
Tie-breaker rule: If two options seem possible, one usually creates a subtle grammar/logic error (agreement, ambiguity, wrong comparison, wrong punctuation strength). Hunt for that.
Key Formulas, Rules & Facts
Punctuation (the highest-yield rules)
| Rule | When to use | Notes / traps |
|---|---|---|
| Comma + FANBOYS (for, and, nor, but, or, yet, so) | To join two ICs | Must have IC on both sides. If the second part isn’t an IC, no comma. |
| Semicolon (;) | To join two ICs closely related | Equivalent “strength” to a period. Don’t use with a dependent clause. |
| IC; however, IC | With conjunctive adverbs (however, therefore, moreover, etc.) | Needs semicolon before and comma after the conjunctive adverb. |
| Colon (:) | After an IC to introduce a list, explanation, or example | Left side must be a complete sentence. Don’t use right after “such as” or “including.” |
| Dash (—) | For emphasis, interruption, or “sudden” add-on | Often interchangeable with colon for an explanation; must be consistent (don’t mix dash types). |
| Comma splice | Never correct | Two ICs joined by only a comma is wrong. Fix with semicolon, period, or comma + FANBOYS. |
| Introductory comma | After an opening phrase/clause | Example: “After the storm, we…” Short intro phrases may omit, but ACT often prefers the comma. |
| Nonessential (nonrestrictive) info | Set off with two commas, two dashes, or parentheses | If you remove it, sentence still makes sense and meaning doesn’t change. |
| Essential (restrictive) info | No commas | If it identifies which one, it’s essential: “Students who studied passed.” |
| Items in a series | Commas between list items | Keep items parallel (same grammar form). |
| Coordinate adjectives | Comma between adjectives if you can swap them / add “and” | “a long, tedious lecture” (yes) vs “two red balloons” (no). |
| Apostrophes | Possession, not plurals | “its” = possessive; “it’s” = it is/it has. |
Sentence Boundaries (fragments & run-ons)
| Problem | What it is | Fixes ACT loves |
|---|---|---|
| Fragment | Missing subject or verb, or starts with a subordinating word (because, although, when…) and never becomes an IC | Attach to nearby IC or rewrite as an IC. |
| Run-on | Two ICs joined with nothing or wrong punctuation | Period, semicolon, or comma + FANBOYS; sometimes add subordinating word. |
Verbs: tense, agreement, and form
| Rule | What to check | Traps |
|---|---|---|
| Subject–verb agreement | Singular subject → singular verb | Ignore prepositional phrases: “The list of items is…” |
| Tense consistency | Match surrounding sentences unless a time shift is intended | Narrative often stays past; general facts often present. |
| Perfect tenses (has/have/had + past participle) | Use when showing sequence or completion relative to another time | Don’t force perfect tense without a “before/after” need. |
| Gerunds/infinitives | Keep form consistent in a list: “enjoys hiking, swimming, and biking” | Don’t mix: “hiking, to swim, and biking.” |
| Active vs passive | Prefer active for clarity and concision | Passive is fine if the doer is unknown/irrelevant, but ACT often rewards active. |
Pronouns
| Rule | How to apply | Traps |
|---|---|---|
| Agreement | Pronoun matches antecedent in number and person | “Each” is singular (but may take “his or her” or “their” depending on test’s style; ACT often accepts singular “their” in modern usage, but watch consistency). |
| Clear reference | It must be obvious what the pronoun refers to | Avoid “this/that/which” with no noun (“this” what?). |
| Case | Subject: I/he/she/we/they; Object: me/him/her/us/them | “Between you and me” (object). For comparisons: “She is taller than I (am).” |
| Who vs whom | Who = subject; whom = object | Replace with he/him: if “him” fits, use whom. |
| That vs which | That = essential; which = nonessential (usually with commas) | ACT tends to reward this distinction. |
Modifiers
| Rule | What to check | Trap |
|---|---|---|
| Modifier placement | Put modifiers next to what they describe | Dangling: “Walking down the street, the trees…” (trees aren’t walking). |
| Adjective vs adverb | Adjectives describe nouns; adverbs describe verbs/adjectives/adverbs | “She sings well” (adverb). |
Parallelism & comparisons
| Rule | Example of correct form | Traps |
|---|---|---|
| Parallel structure | “She likes reading, writing, and painting.” | After “both/and,” “either/or,” “not only/but also,” keep grammar matched. |
| Logical comparison | Compare like with like: “Her salary is higher than his.” | Don’t compare a person to a thing they own: “higher than him” is ambiguous. |
Concision & style (rhetorical skills)
| Preference | What it means | Watch out |
|---|---|---|
| Shortest that preserves meaning | Cut redundancy and empty phrases | Don’t cut necessary detail or change tone. |
| Avoid redundancy | “each and every,” “completely finished,” “in my opinion” | If meaning repeats, delete. |
| Specific nouns/verbs | “experiment showed” beats “thing did” | Vague “this/that/which” without a noun is weak. |
| Maintain consistent tone | Formal vs casual | Don’t insert slang into a formal passage. |
Organization, transitions, and writing strategy
| Task | What ACT wants | Quick check |
|---|---|---|
| Transitions | Logical relationship: addition, contrast, cause/effect, example, sequence | Read the sentence before/after and name the relationship. |
| Best place for a sentence | Where it fits logically (topic then detail) | Look for pronouns (“this,” “they”) needing an antecedent. |
| Add/delete | Keep only relevant info supporting the paragraph’s point | If it’s off-topic or repetitive, delete. |
| Introductions/conclusions | Intro previews; conclusion wraps up | Don’t introduce brand-new main ideas in a conclusion. |
Examples & Applications
Example 1: Commas vs semicolons
Sentence: “The exhibit opened early, many visitors arrived before noon.”
- You have two independent clauses: “The exhibit opened early” + “many visitors arrived before noon.”
- A comma alone creates a comma splice.
Best fixes: - “The exhibit opened early; many visitors arrived before noon.”
- “The exhibit opened early, and many visitors arrived before noon.”
Example 2: Essential vs nonessential clauses
Sentence: “My brother, who lives in Seattle, is visiting.”
- The commas imply nonessential: you have only one brother (extra info: he lives in Seattle).
If you have multiple brothers: - “My brother who lives in Seattle is visiting.” (no commas = essential, identifies which brother)
Example 3: Dangling modifier
Wrong: “After reading the article, the conclusion seemed obvious.”
- Who read the article? Not “the conclusion.”
Fix: “After reading the article, I found the conclusion obvious.”
Example 4: Transition logic
Context: Sentence 1 says a method is expensive; Sentence 2 says a cheaper alternative exists.
- Best transition is contrast: “However,” “In contrast,” “Nevertheless,”
- Wrong would be “Therefore,” (cause/effect) or “Moreover,” (addition)
Common Mistakes & Traps
Comma splice blindness
- Wrong: Joining two complete sentences with a comma.
- Why wrong: Comma isn’t strong enough to join IC + IC alone.
- Avoid: Use semicolon/period or comma + FANBOYS.
Misidentifying an independent clause
- Wrong: Using a semicolon/colon when one side isn’t a full sentence.
- Why wrong: Semicolons/periods require IC on both sides (colon requires IC before it).
- Avoid: Do the quick test: can it stand alone?
Comma errors with essential vs nonessential information
- Wrong: Adding commas around information that defines which noun you mean.
- Why wrong: Commas change meaning by implying the info is optional.
- Avoid: Ask: “Do I need this to know which one?” If yes, no commas.
Dangling/misplaced modifiers
- Wrong: Opening phrase modifies the wrong noun.
- Why wrong: Creates illogical meaning.
- Avoid: Put the noun right after the modifier (“After jogging, I…”).
Pronoun ambiguity
- Wrong: “This shows…” “They say…” when “this/they” is unclear.
- Why wrong: Reader can’t tell what the pronoun refers to.
- Avoid: Replace with a clear noun: “This result shows…”
Subject–verb agreement traps with interrupting phrases
- Wrong: “The bouquet of roses smell nice.”
- Why wrong: Subject is “bouquet” (singular).
- Avoid: Cross out prepositional phrase (“of roses”).
Nonparallel lists and paired structures
- Wrong: “She likes to run, swimming, and bikes.”
- Why wrong: Mixed grammar forms disrupt clarity.
- Avoid: Keep consistent forms after “to,” after prepositions, and in lists.
Choosing the shortest option that changes meaning
- Wrong: Cutting a qualifier that the sentence needs.
- Why wrong: ACT rewards concision only when meaning and tone stay intact.
- Avoid: Re-read: did you lose a key detail or logical connection?
Memory Aids & Quick Tricks
| Trick / mnemonic | What it helps you remember | When to use it |
|---|---|---|
| IC + IC needs BIG glue | Two complete sentences need period, semicolon, or comma + FANBOYS | Any time punctuation is testing sentence boundaries |
| FANBOYS | for, and, nor, but, or, yet, so | Choosing a conjunction to join ICs |
| “Take it out” test | If you can remove the phrase and the sentence still works + meaning doesn’t change → nonessential | Commas around clauses/phrases |
| He/Him test | If “he” fits → who; if “him” fits → whom | Who/whom questions |
| “Which = comma friend” | “which” often signals nonessential info set off by commas | That vs which choices |
| Arrow test for modifiers | Draw an arrow from modifier to the noun it describes; it should point to the correct word right next to it | Misplaced/dangling modifier questions |
| “Shortest + same meaning” | ACT style: cut fluff, keep meaning | Wordiness/redundancy questions |
Quick Review Checklist
- Can you spot independent clauses quickly?
- Do you avoid comma splices (comma alone between two ICs)?
- Do you know when to use semicolon vs comma + FANBOYS?
- Do you remember: colon must follow an IC?
- Can you apply essential vs nonessential (commas change meaning)?
- Do your verbs match the true subject (ignore interrupting phrases)?
- Are pronouns clear and in the correct case (I/me, who/whom)?
- Are lists and paired structures parallel?
- In style questions, do you choose the clearest, most concise option that keeps meaning and tone?
- For transitions/organization, do you read surrounding sentences and name the logical relationship?
You don’t need perfect intuition—just keep applying the rules systematically and you’ll rack up points fast.