An adjective is a word or set of words that modifies (i.e., describes) a noun or pronoun. Adjectives may come before the word they modify.
Examples:
That is a cute puppy.
She likes a high school senior.
Adjectives may also follow the word they modify:
Examples:
That puppy looks cute.
The technology is state-of-the-art.
An adverb is a word or set of words that modifies verbs, adjectives, or other adverbs. Adverbs answer how, when, where, why, or to what extent—how often or how much (e.g., daily, completely).
Examples:
He speaks slowly (tells how)
He speaks very slowly (the adverb very tells how slowly)
She arrived today (tells when)
She will arrive in an hour (this adverb phrase tells when)
Let's go outside (tells where)
We looked in the basement (this adverb phrase tells where)
Bernie left to avoid trouble (this adverb phrase tells why)
Jorge works out strenuously (tells to what extent)
Jorge works out whenever possible (this adverb phrase tells to what extent)
