Here's why:
* Adverbs modify verbs, adjectives, or other adverbs. They describe how, when, where, or to what extent something happens.
* Nouns are words that name people, places, things, or ideas.
* Verbs are words that describe actions or states of being.
Example:
"She gazed dreamily at the sunset."
In this sentence, "dreamily" describes how she gazed, making it an adverb modifying the verb "gazed."