How same words can be used as an adverb and adjective in sentences?

There are several words which are used both as adjectives and as adverbs. Here are a few examples of such words: fast, half, straight, just, late, early, etc.

1. fast: He is a fast runner. (adjective, as it modifies a noun)

            He drove the car fast. (adverb, as it modifies a verb)

2. late: The class is scheduled for late evening. (adjective, as it modifies a noun)

            He arrived late. (adverb, as it modifies a verb)