what is the purpose of adverb

An adverb is a word that describes - or modifies, as grammarians put it - a verb, an adjective or another adverb. It is easy to see how adverbs describe, or modify, verbs, since they simply explain most about the action. For example: He quickly runs.

Semoga membantu :3

Adverb dalam bahasa indonesia artinya kata keterangan.
contoh :
Beautifully = Dengan cantiknya
Fluently = Dengan fasihnya
Happily = Dengan gembira

Tetapi untuk fast dan hard tetap, tidak ditambah ly dibelakang.