An adverb is a word that modifies a noun, an adjective, or another adverb. It tells us to what degree something happens, how much of it happens, when, how and why it also happened. Adjectives are words used to describe a noun or pronoun.
In the first sentence, the adverb 'very', modified the adjective, 'quiet'. The adverb tells us to what degree the house is quiet.
