good vs. well

Good is an adjective (good performance). Well is an adverb when it modifies a verb (speak well). The use of the adjective good in place of the adverb well to modify a verb is especially common in casual and nonstandard speech.

Example sentence with editing. Original sentence: An echocardiogram shows how good your heart works under stress. Revised sentence: An echocardiogram shows how well your heart works under stress.

The adverb well should be used to modify the verbs had done and works.

Confusion can arise because well is an adjective when it modifies a noun or pronoun and means “healthy” or “satisfactory.” Both good and well can be used to refer to health, although many writers feel that well sounds more formal.

Example sentence: The babies were well and warm.

Example sentence: Adrian did not feel well, but she made her presentation anyway.

Exercises:

Adjectives and adverbs 1

Adjectives and adverbs 2

Adjectives and adverbs 3