Like bad and badly, good and well are often mistakenly interchanged. However, if you keep in mind that good is always an adjective, you will avoid switching it with well.

On the other hand, well can be used as an adjective or as an adverb.

• As an adjective, it follows a linking verb and describes a person's health.

• As an adverb, it goes with the action verb that it describes.

Well as an adjective

Sylvia is not feeling well when she arrived from her trip to the province.

After two weeks, she appeared well and happy.

Well as an adverb

Animals such as the anteater, jaguar, and lemur live well in tropical rain forests.

They survive well in these habitats.

Good

It is a good idea to use mountain yaks for trekking.

The cool wind atop a hill is good for the lungs.