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 standard academic 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. Good and bad are always adjectives, and both can be used after a linking verb.

Badly is an adverb and can modify a verb, an adjective, or another adverb. After a linking verb, use bad instead.

The linking verb feel requires the adjective bad.

As an adjective, well means “in good health”; as an adverb, it means “in a good way” or “thoroughly.”