An adverb is a word that modifies or describes a verb, adjective, or other adverb. Adverbs provide more information about how, when, where, why, or to what extent an action takes place, or how an adjective or another adverb is qualified. Adverbs can be used to add detail to a sentence and provide a more complete picture of what is happening. Examples of adverbs include quickly, slowly, loudly, quietly, often, rarely, and so on.
Here are some examples of adverbs and how they modify different parts of speech:
She sings beautifully. (Here, "beautifully" is an adverb modifying the verb "sings" and describing how she sings.)
The car moved slowly. (Here, "slowly" is an adverb modifying the verb "moved" and describing how the car moved.)
He spoke very quietly. (Here, "very" is an adverb modifying the adverb "quietly" and intensifying the degree to which he spoke quietly.)
The food smells deliciously. (Here, "deliciously" is an adverb modifying the verb "smells" and describing how the food smells.)
She is extremely intelligent. (Here, "extremely" is an adverb modifying the adjective "intelligent" and intensifying the degree to which she is intelligent.)
Note that some adverbs can also modify an entire sentence, expressing the speaker's attitude, viewpoint, or evaluation of the content. For example: Frankly, I don't care what you think. (Here, "frankly" is an adverb modifying the whole sentence and indicating the speaker's attitude towards the listener's opinion.)