How do you choose correctly among the commonly confused word pairs the ACT tests, such as their/there/they're, your/you're, and affect/effect?
Commonly confused words on ACT English: distinguishing homophone and near-homophone pairs (their/there/they're, your/you're, its/it's, then/than, affect/effect, fewer/less, who's/whose) by meaning and part of speech, and choosing the spelling that fits the sentence.
A focused answer to commonly confused words on ACT English: telling apart homophone and near-homophone pairs (their/there/they're, your/you're, its/it's, then/than, affect/effect, fewer/less) by meaning and part of speech, with quick tests and a routine for choosing the right word in an underlined portion.
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What this skill is asking
The ACT plants commonly confused words, pairs and trios that sound alike or nearly alike but differ in meaning and part of speech, and asks you to choose the right one. These are pure usage points: there is one correct word for the sentence, decided by meaning and grammar, not by sound (since the wrong choices sound the same when read aloud). Knowing the distinctions and a quick test for each makes these reliable.
The high-frequency sets
A short list of confusions covers most of what the ACT asks. Learn the meaning and the quick test for each.
Tests that settle each set
Two simple tests handle most of the sets: expand the contraction, and check the part of speech.
These tests convert a sound-alike guess into a clear decision. Because all four options often sound identical when read, reading by ear is useless here; the meaning and grammar are the only guides.
Applying it to an underlined portion
Identify the needed meaning, then pick the matching spelling.
Why these are easy points once learned
Commonly confused words are a closed list with clear rules, so they reward memorization plus two tests (expand the contraction; check the part of speech). Because the wrong options are deliberately homophones, the ACT is testing whether you know the distinction, not whether you can hear it. The topic overlaps with apostrophes (its/it's, who's/whose are also apostrophe questions) and with word choice (precise usage). Drill the sets and apply the tests, and these become some of the most dependable points on the section.
Try this
Q1. How do you test the contraction pairs like they're/their, you're/your, and it's/its? [Recall]
- Cue. Expand the contraction to its two-word form and see if it fits the sentence: "they're" = "they are", "you're" = "you are", "it's" = "it is/has". If the expansion fits, use the contraction; if not, use the possessive (their, your, its).
Q2. A sentence reads "The medicine had a strong affect, but it did not affect her sleep." Is each word correct? Explain. [Short explanation]
- Cue. The second is correct but the first is wrong. "Affect" is the verb (to influence), so "did not affect her sleep" is right. But "a strong affect" needs the noun "effect" (a result): "a strong effect". So it should read "had a strong effect, but it did not affect her sleep."
Exam-style practice questions
Practice questions written in the style of ACT exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
ACT English (style)1 marksChoose the best option: 'The students left there backpacks in they're lockers over their.' (A) NO CHANGE (B) their backpacks in their lockers over there (C) they're backpacks in there lockers over their (D) there backpacks in their lockers over they'reShow worked answer →
The correct answer is (B), "their backpacks in their lockers over there". "Their" is the possessive (the backpacks and lockers belong to the students); "there" indicates a place ("over there"). The original mixes all three forms up.
Why not the others: (A), (C), and (D) each misuse at least one form. "They're" means "they are" and fits none of these slots; "there" is a place; "their" shows possession. Two possessives ("their backpacks", "their lockers") and one place word ("over there") make (B) correct.
ACT English (style)1 marksChoose the best option: 'The new rule will effect every student, and its affects will be felt for years.' (A) NO CHANGE (B) affect every student, and its effects (C) effect every student, and its effects (D) affect every student, and its affectsShow worked answer →
The correct answer is (B), "affect every student, and its effects". "Affect" is usually the verb (to influence): the rule will affect students. "Effect" is usually the noun (a result): its effects will be felt. The original swaps them.
Why not the others: (A) uses "effect" as a verb and "affects" as a noun, both backwards; (C) keeps the verb "effect" (wrong, should be "affect"); (D) uses "affects" as a noun (should be "effects"). Verb "affect", noun "effect".
Related dot points
- Apostrophes and possessives on ACT English: using an apostrophe for possession (singular adds 's, plural ending in s adds just an apostrophe) and for contractions, distinguishing its from it's and whose from who's, and rejecting the apostrophe in a plain plural that shows no possession.
A focused answer to apostrophes on ACT English: forming singular and plural possessives, using apostrophes for contractions, telling its from it's and whose from who's, and rejecting the stray apostrophe in a plain plural, with a routine for choosing the right form in an underlined portion.
- Word choice and precision on ACT English: selecting the word whose denotation and connotation exactly fit the sentence's meaning and context, rejecting vague or approximately right words, and using surrounding context to pick the precise term in an underlined portion.
A focused answer to word choice and precision on ACT English: choosing the word whose exact meaning and connotation fit the context, telling a precise choice from a vague or approximately right one, and using the surrounding sentence to pick the right term, with a routine for the underlined word.
- Pronoun agreement and reference on ACT English: matching a pronoun to its antecedent in number (singular antecedents, including indefinite pronouns, take singular pronouns), and fixing unclear reference where a pronoun has no clear antecedent or could point to more than one noun.
A focused answer to pronoun agreement and reference on ACT English: matching a pronoun to its antecedent in number, treating indefinite pronouns and collective nouns correctly, and fixing vague or ambiguous reference where a pronoun has no clear or single antecedent, with a routine for the underlined pronoun.
- Subject-verb agreement on ACT English: matching a verb to its true subject in number, ignoring prepositional phrases and other words between subject and verb, and handling tricky subjects (indefinite pronouns, compound subjects, collective nouns, and inverted there-is and here-are structures).
A focused answer to subject-verb agreement on ACT English: finding the true subject and matching the verb in number, ignoring phrases that come between them, and handling indefinite pronouns, compound subjects, collective nouns, and inverted there-is structures, with a routine for the underlined verb.
Sources & how we know this
- Description of the ACT English Test — ACT, Inc. (2025)
- Preparing for the ACT Test — ACT, Inc. (2025)