1. Verbs: They describe how, when, where, or to what extent an action is performed.
* Example: She quickly ran to the store. (modifies the verb "ran")
2. Adjectives: They describe the degree or intensity of an adjective.
* Example: The dog is very happy. (modifies the adjective "happy")
3. Other adverbs: They can modify another adverb, providing further detail about how, when, where, or to what extent the adverb applies.
* Example: He spoke extremely slowly to the child. (modifies the adverb "slowly")