Adjectives describe nouns; adverbs describe verbs, adjectives, or other adverbs—on the ACT, pick the form that matches what is being modified, not the one that merely "sounds fancy." "She runs quick" fails because a verb needs an adverb: quickly.
The core rule
- Adjective → noun: a careful driver
- Adverb → verb: drives carefully
- Adverb → adjective: extremely careful
Part of ACT English grammar rules.
ACT favorites
- Linking verbs (feel, look, smell, taste, sound) take adjectives describing the subject: She feels bad (not badly for emotion).
- Comparatives (better, faster) vs superlatives (best, fastest) with two vs many items.
- Good (adjective) vs well (adverb for how something is done)—She plays well.
Quick check
Ask: what word is being modified? If it is a verb, you usually need -ly. If it is a noun, you need an adjective. Pair with parallel structure when lists mix forms.
Start practicing
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