Is is not an adverb it is a be verb. Be verbs are:
present -- am is are
past -- was were
It is time adverb
It is an adverb of degree.
Adverb of Degree
adverb of degree
There is no adverb derived from type. Not every word has a corresponding noun verb adverb adjective etc
It's an adverb of time.
Avoid is not any type of adverb because it's a verb.
No, it is an adverb of indefinite time. This is another type of adverb of time.
when
adverb of frequency, like - sometimes always often
The word "best" is a comparative (superlative) adjective, not an adverb.
An adverb. Almost all adverb end in ly