Adjectives vs Adverbs
These two parts of speech serve different descriptive purposes in a sentence.
Adjectives
Adjectives describe or modify nouns (people, places, things). They tell us 'what kind'.
She is a careful driver. The slow turtle won the race.
Adverbs
Adverbs modify verbs, adjectives, or other adverbs. They tell us 'how', 'when', or 'where'. They often end in -ly.
She drives carefully. (Modifies the verb 'drives') The turtle walked slowly.
Exceptions (Irregular Adverbs)
Some adverbs don't end in -ly and look exactly like their adjectives: fast, hard, late, early.
Good is an adjective; well is its adverb. (He is a good singer. He sings well.)