1. A Preposition.
The novel was published BY...
2. An Adverb.
She works close BY.
3. An Adjective.
There will be a by-election for ....
part of speech
what part of speech is beneath
The part of speech is a adjective
adverb
what part of speech is work
An adjective is a part of speech.
The part of speech that asks: how, when, and where, are adverbs.
The part of speech which "antagonist" is, is noun.
The part of speech of cannot is a verb
the part of speech sashay is a averb
The part of speech for peculiar is an adjective.
Did is a verb, and not is an adverb. Didn't is not any part of speech. It's a contraction of did and not.