Good
Good is an adjective. It modifies (describes) a noun.
Example
As the above examples show, the adjective good has three usual positions:
1. before the noun it modifies (good time)
2. after a verb of being (play was good)
3. after a linking verb (flowers smell good)
In each case, the adjective good is modifying a noun.
Good should never be used as an adverb (modifying a verb).
Thus, the following example is incorrect:
As shown below, the adverb well should be used in the above example.
Correct:
Well
Well is an adverb.
Well always modifies/describes a verb.
As a modifier of a verb, well tells HOW something is done.
In the above example, well tells how Hans did on his test.
More examples:
Well tells
how Max plays chess.
Well
tells how Jan is loved by her friends..
In certain cases, well may be used as an adjective and is interchangeable with good:
1. to indicate good health
Both of the following examples are correct:
2. to indicate satisfactory conditions
Both of the following examples are correct:
Both good and well change to better and best in their comparative and superlative forms.
Use the comparative form - better - when comparing two items.
Examples - better as adjective
Example - better as adverb
Use the superlative form - best - when comparing three or more items.
Examples - best as adjective
Example - best as adverb
Summary:
Good is an adjective. It modifies a noun.
Well is an adverb. It modifies a verb (telling "how").
Well may be used as an adjective to indicate good health or satisfactory conditions.