Adverbs modify verbs. Adverbs are often recognized by their -ly ending, but not all adverbs end in -ly.
Adverbs can tell where something is happening: farther, closer, nearer, below, between, above, behind
The dog moved closer.
We sat on the porch while the tree leaves rustled above.
Sally ran farther than her brother.
Adverbs can tell when something is happening: today, tomorrow, yesterday, soon, now, then, forever
The bell is ringing now.
John pitched yesterday in a practice game.
We soon found the answer.
Adverbs can tell how frequently something is happening: never, seldom, often, usually, always, sometimes
My dog seldom sleeps in his own bed.
My brother always sings in the shower.
We often eat pizza on Friday nights.
Some adverbs do not end in -ly. Adverbs can tell where something happens, when something happens, and how frequently something happens.