How do you choose between an adjective and an adverb on the ACT, and how do you form comparatives and superlatives correctly?
Adjectives, adverbs, and comparisons on ACT English: using adjectives to describe nouns and adverbs to describe verbs, adjectives, and other adverbs (good versus well), and forming comparatives (for two) and superlatives (for three or more) without doubling, such as more taller.
A focused answer to adjectives, adverbs, and comparisons on ACT English: using adjectives for nouns and adverbs for verbs and adjectives (good versus well, real versus really), and forming comparatives for two things and superlatives for three or more without doubling, with a routine for the underlined modifier.
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What this skill is asking
Adjectives describe nouns, and adverbs describe verbs, adjectives, and other adverbs. The ACT tests whether you pick the right one (the classic "good" versus "well"), and whether you form comparisons correctly: the comparative for two things, the superlative for three or more, with no doubling. These are rule-based decisions, so they reward knowing the rules over going by ear.
Adjective or adverb
The first decision is which word the modifier describes.
The most tested pair is good/well (and real/really, bad/badly). "Good" and "real" and "bad" are adjectives; "well" and "really" and "badly" are adverbs. "She sings good" is wrong because "sings" is a verb; use "sings well". One exception: after linking verbs about health, "well" can be an adjective ("I feel well"), but "I feel good" is also standard for a state of being.
Comparatives and superlatives
The second decision is the form of a comparison, set by how many things are compared.
The doubling error is a giveaway: any option with "more" plus an -er word, or "most" plus an -est word, is wrong. And short versus long adjectives decide -er/-est versus more/most: "beautiful" takes "more beautiful" (not "beautifuler"), while "tall" takes "taller" (not "more tall").
Applying it to an underlined modifier
Run the two checks: what is modified, and how many are compared.
Why two checks settle this topic
Modifier questions look like vocabulary, but they are two mechanical checks: adjective or adverb (what is being described) and comparative or superlative (how many are compared), plus the no-doubling rule. Signal phrases ("of the two", "of all") and the good/well pair cover most of what the ACT asks. The topic overlaps with parallel structure (comparisons must compare like with like) and with word choice (the precise modifier). Apply the checks and these become quick, rule-decided points.
Try this
Q1. How do you decide between an adjective and an adverb, and what is the rule for "good" versus "well"? [Recall]
- Cue. Find the word being modified: a noun takes an adjective, while a verb, adjective, or adverb takes an adverb. "Good" is an adjective (describes a noun: "a good game"); "well" is the adverb (describes a verb: "played well").
Q2. A sentence compares two players and reads "Of the two guards, he is the quickest." What is wrong, and how do you fix it? [Short explanation]
- Cue. "Quickest" is the superlative, used for three or more, but only two guards are compared. Use the comparative for two: "Of the two guards, he is the quicker." The phrase "of the two" signals a comparative, not a superlative.
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 team played really good in the final.' (A) NO CHANGE (B) really well (C) real good (D) real wellShow worked answer →
The correct answer is (B), "really well". "Played" is a verb, so it needs an adverb to describe how the team played: "well" (the adverb), modified by "really" (an adverb modifying "well"). "Good" is an adjective and cannot describe the verb "played".
Why not the others: (A) "good" is an adjective, wrong for describing a verb; (C) "real good" uses two words wrongly ("real" is an adjective, not an adverb, and "good" is still an adjective); (D) "real well" uses the adjective "real" where the adverb "really" is needed. Adverbs describe verbs: "played well".
ACT English (style)1 marksChoose the best option: 'Of the two routes, the coastal one is the most scenic.' (A) NO CHANGE (B) more scenic (C) most scenicest (D) scenicerShow worked answer →
The correct answer is (B), "more scenic". When comparing exactly two things, use the comparative ("more scenic"), not the superlative ("most scenic"). The phrase "of the two routes" signals a two-way comparison.
Why not the others: (A) "most scenic" is the superlative, used for three or more, not two; (C) "most scenicest" doubles the superlative, which is always wrong; (D) "scenicer" is not a valid form (long adjectives use "more", not "-er"). For two things, the comparative "more scenic" is correct.
Related dot points
- Parallel structure on ACT English: matching the grammatical form of items in a series, a pair, or a comparison so each element is the same kind (all nouns, all -ing forms, all clauses), and keeping correlative pairs (not only/but also, either/or) and than/as comparisons parallel.
A focused answer to parallel structure on ACT English: making items in a series, a pair, or a comparison share the same grammatical form, and keeping correlative conjunctions (not only/but also, either/or) and than/as comparisons parallel, with a routine for fixing the odd element in an underlined portion.
- Pronoun case on ACT English: choosing the subject case (I, he, she, we, they, who) for subjects and the object case (me, him, her, us, them, whom) for objects, and handling the test's favorite cases (compounds like 'my friend and I/me', comparisons with than, and who versus whom).
A focused answer to pronoun case on ACT English: using subject pronouns (I, he, she, we, they, who) for subjects and object pronouns (me, him, her, us, them, whom) for objects, and the tricky cases of compound subjects and objects, comparisons with than or as, and who versus whom, with a drop-the-other-noun test.
- 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.
- 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.
Sources & how we know this
- Description of the ACT English Test — ACT, Inc. (2025)
- Preparing for the ACT Test — ACT, Inc. (2025)