RULES

The Position of the Adverb in a Sentence

An adverb of frequency goes before a main verb (except with To Be).

Subject + adverb + main verb
I always remember to do my homework.
He normally gets good marks in exams.

An adverb of frequency goes after the verb To Be.

Subject + to be + adverb
They are never pleased to see me.
She isn't usually bad tempered.

When we use an auxiliary verb (have, will, must, might, could, would, can, etc.), the adverb is placed between the auxiliary and the main verb. This is also true for to be.

Subject + auxiliary + adverb + main verb
She can sometimes beat me in a race.
I would hardly ever be unkind to someone.
They might never see each other again.
They could occasionally be heard laughing.