Listen ! Helen is singing in the next room.—It __________ be Helen. She is in Tianjinnow.

I’m a teenager’s mother. Sometimes I don’t know ____.—Maybe he suffers from stress.

Don’t be ________ by products promising to makeyou lose weight quickly.

She _________ wash the dishes now.

My father ______________ dinner at restaurants last year， but now he usually comes back home from work and cooks supper for us.