Grammar and Usage

Grammar and Usage is one of the most heavily tested areas on the ACT English section. These questions evaluate your ability to recognize and correct errors in standard written English, including issues with agreement, verb forms, pronoun usage, and word choice. Mastering these rules will help you answer questions quickly and accurately on test day.

Subject-Verb Agreement

The subject and verb in a sentence must agree in number. A singular subject takes a singular verb, and a plural subject takes a plural verb. The ACT loves to hide the true subject by placing long phrases between it and the verb.

Step-by-step approach for agreement questions:

1. Find the verb that is underlined or being tested.
2. Trace back to the true subject — skip over prepositional phrases, appositives, and relative clauses.
3. Determine whether the subject is singular or plural.
4. Match the verb to the subject.

Additional worked examples:

• Indefinite pronoun trap: "Everyone in the advanced classes has completed the assignment." (NOT "have" — "everyone" is always singular, no matter what follows it.)
• "There are/is" construction: "There are several reasons for the delay." (The subject is "reasons," which is plural — do not be fooled by "there.")
• Collective noun: "The committee has reached its decision." (The committee acts as one unit = singular.)

Pronoun-Antecedent Agreement

A pronoun must agree with its antecedent (the noun it replaces) in number, gender, and person.

• Singular indefinites: Each, every, everyone, anyone, someone, nobody — all take singular pronouns. "Each student must bring his or her own calculator."
• Collective nouns: Team, group, committee, family — usually singular. "The team celebrated its victory."
• Ambiguous references: "When Maria told Lucia the news, she was surprised" — who was surprised? Rewrite for clarity: "Maria was surprised when she heard the news from Lucia."
• Vague pronouns: Avoid "this," "that," "it," or "which" without a clear antecedent. "The company raised prices, which angered customers" — what exactly does "which" refer to?

More pronoun examples:

• "Neither the coach nor the players could hide their disappointment." — "their" matches the nearest antecedent "players" (plural).
• "A student should always proofread his or her essay before submitting it." — "A student" is singular, so the pronoun must be singular too. (On the ACT, singular "they" is not yet standard.)
• Shift in person: "When one studies hard, you can succeed." This incorrectly shifts from "one" to "you." Fix: "When one studies hard, one can succeed" or "When you study hard, you can succeed."

Pronoun Case

Use subjective case (I, he, she, we, they) for subjects and predicate nominatives. Use objective case (me, him, her, us, them) for objects of verbs and prepositions.
Who vs. Whom — the quick test:
Replace the pronoun with "he" or "him." If "he" fits, use "who." If "him" fits, use "whom."

• "The author who wrote the novel..." (he wrote the novel → who)
• "The author whom I admire..." (I admire him → whom)
• "To whom should I address the letter?" (I should address it to him → whom)

Verb Tense and Form

Verb tenses must be consistent and logical within a sentence and across a passage.

• Tense consistency: Don't shift tenses without reason: "She walked to the door and opens it" — both should be past tense: "walked...opened."
• Past perfect: Use "had + past participle" for an action completed before another past action: "By the time we arrived, the show had already started."
• Irregular verbs: The bell rang (not "ringed"), she has written (not "wrote"), they had begun (not "began").
• Subjunctive mood: Use "were" (not "was") in hypothetical or contrary-to-fact clauses: "If I were you, I would study harder."

Example — tense shift error:
"The explorers traveled through the desert for weeks. They carry very little water and relied on oases they found along the way."
The error is "carry" — it should be "carried" to stay consistent with the past tense established by "traveled" and "relied."

More tense examples:

• Present perfect vs. simple past: "She has lived here since 2010" (started in the past, still true). "She lived here in 2010" (no longer lives here).
• Would/will confusion: "He said he would arrive by noon" (not "will" — indirect speech in a past context shifts "will" to "would").

Adjectives vs. Adverbs

Adjectives modify nouns; adverbs modify verbs, adjectives, or other adverbs.

• "She sings beautifully" (adverb modifying the verb "sings").
• "She has a beautiful voice" (adjective modifying the noun "voice").
• Linking verbs: After linking verbs (is, seems, feels, looks, smells, tastes), use an adjective: "The soup smells good" (not "well," unless you mean the ability to smell).
• Common ACT trap: "She did really well on the test" (not "real well" — "really" is the adverb modifying "well").

More adjective/adverb examples:

• "The engine runs smoothly" (adverb — how does it run?). NOT "The engine runs smooth."
• "She felt bad about the mistake" (adjective after linking verb "felt"). NOT "She felt badly" — that would mean her sense of touch is impaired.

Comparatives and Superlatives

Use comparatives (-er / more) when comparing two things and superlatives (-est / most) for three or more.

• "She is taller than her sister." (comparing two people)
• "He is the tallest in the class." (comparing three or more)
• Never double up: "more better" or "most easiest" are always wrong on the ACT.
• Irregular forms: good → better → best; bad → worse → worst; far → farther → farthest.

Idiomatic Expressions

Some word combinations are simply conventions of English. Common ACT idioms include:

• "different from" (not "different than")
• "between X and Y" (not "between X or Y")
• "regard as" (not "regard to be")
• "try to" (not "try and")
• "not so much X as Y" (not "not so much X but Y")
• "prefer X to Y" (not "prefer X over Y")

Common Mistakes: Top 5 ACT Grammar Traps

1. Long intervening phrases: "The collection of rare, antique stamps from the 19th century is valuable." Students pick "are" because "stamps" is nearby — but the subject is "collection" (singular).
2. "Each" and "every" are always singular: "Every one of the contestants was nervous." Despite "contestants" being plural, "every one" is singular.
3. Pronoun shifts: A passage uses "one" throughout, then an answer choice suddenly switches to "you" or "they." Stay consistent with the passage.
4. Irregular past participles: "She had swum across the lake" (not "swam"). "The pipe had burst" (not "bursted"). These get tested more than you would expect.
5. "Less" vs. "fewer": Use "fewer" for countable items ("fewer books") and "less" for uncountable quantities ("less water"). The ACT tests this occasionally.

"NO CHANGE" Strategy

On the ACT English section, the first answer choice (A or F) is always "NO CHANGE," meaning the underlined portion is already correct as written. Many students are reluctant to pick "NO CHANGE" because they assume there must be an error. Here is how to handle it:

• NO CHANGE is correct about 25% of the time — roughly one in four questions. Do not be afraid to pick it.
• Test the original first: Read the sentence with the underlined portion as-is. If it follows every grammar rule and sounds correct, strongly consider NO CHANGE.
• Check the other options: Even if the original looks correct, quickly scan B/C/D. If none of them fix a real problem — and they introduce awkwardness or new errors — pick NO CHANGE with confidence.
• Do NOT pick NO CHANGE just because you cannot identify the error. If you are unsure, use elimination: if two or three options clearly have errors, pick the remaining one, whether it is NO CHANGE or not.

Practice Walkthrough

ACT-style passage question — work through it step by step:

Passage excerpt: "The group of scientists who has been studying the effects of climate change on coral reefs published their findings last month."

(A) NO CHANGE
(B) have been studying
(C) was studying
(D) are studying

Step 1 — Identify what is being tested: The underlined verb "has been studying." This is a subject-verb agreement question.
Step 2 — Find the true subject: "The group of scientists who ___" — but wait. The verb "has been studying" is inside a relative clause modifying "scientists," not "group." The relative pronoun "who" refers to "scientists" (plural).
Step 3 — Apply the rule: "Scientists" is plural, so the verb must be plural: "have been studying."
Step 4 — Eliminate wrong answers:

• (A) NO CHANGE — "has" is singular. Incorrect for "scientists."
• (B) "have been studying" — plural, matches "scientists." Keeps present perfect progressive (logical: they studied and published). Correct.
• (C) "was studying" — singular, and shifts away from present perfect. Incorrect.
• (D) "are studying" — present tense, but the sentence says they "published" (past). This creates a tense inconsistency. Incorrect.

Answer: (B)

Tips for the ACT

• Read the entire sentence before choosing an answer — context matters.
• Identify the rule being tested. Once you know which grammar concept is at play, apply the rule directly.
• Simplest is best: When in doubt, the most concise correct option is usually the right answer.
• Eliminate new errors: Cross off answers that fix one issue but introduce another.
• Trust your ear, then verify: If something "sounds wrong," figure out why using a specific grammar rule.
• Find the subject: The ACT loves to separate subjects from verbs with long phrases — always trace back to the true subject.
• Time tip: Grammar questions are usually fast. Aim for 30-40 seconds per question to save time for rhetorical strategy questions.
• Process of elimination: With only 4 answer choices on the ACT, eliminating even one bad option gives you a strong chance. Eliminate two and you are very likely to get the point.
• When the shortest answer is grammatically correct, pick it. The ACT almost never rewards unnecessary words.