The bold word is a verb. Which adverb describes it?

Supergirl arrived at the Anime Club meeting early.

arrived

"early" would be the adverb describing the verb ("arrived").

Explanation:

When thinking of an adverb, one can distinguish it by asking themselves "how did the verb occur?", or "how did the subject verb? (and replace "subject" and "verb" with the respective words from the sentence) ". In this case, you would ask yourself, "how did Supergirl arrive at the Anime Club?" The answer would be, "early".