When adjectives come after linking verbs (such as is), they usually describe the subject: I am patient. Note that in specific sentences, some verbs may or may not be linking verbs—appear, become, feel, grow, look, make, prove, seem, smell, sound, and taste, for instance. When a word following one of these verbs modifies the subject, use an adjective; when it modifies the verb, use an adverb.

Linking verbs suggest a state of being, not an action. In the preceding examples, looked angry suggests the state of being angry; looked angrily suggests an angry action.

In everyday conversation, you will often hear (and perhaps use) adjectives in place of adverbs. For example, people often say go quick instead of go quickly. When you write in academic and professional English, however, use adverbs to modify verbs, adjectives, and other adverbs.

Good, well, bad, and badly. The modifiers good, well, bad, and badly cause problems for many writers because the distinctions between good and well and between bad and badly are often not observed in conversation. Problems also arise because well can function as either an adjective or an adverb.