POSITION OF ADVERBS IN SENTENCES
Frequency adverbs generally go before the main verb, but they go after the verb be:
I usually get up at 7.30. BUT I am often late.
Students often make mistakes with this, e.g. I often am late.
Also note that the adverb sometimes can also go at the beginning or end of a sentence, e.g.
Sometimes I go shopping on Saturdays. I go shopping on Saturdays sometimes