An INTERROGATIVE ADVERB is an adverb that asks a question about place, time, manner, or reason.

Why is an interrogative adverb?

The interrogative adverbs are why, where, when, and how. They are used to ask questions.

Which are the adverbs of frequency?

An adverb of frequency describes how often an action happens. There are six main adverbs of frequency that we use in English: always, usually (or normally), often, sometimes, rarely, and never. How do you usually introduce or elicit these from your students?