Our parents have done a lot for us. I think we should ______ them by working hard.

The boy is ________ the room.

I find this Math problems very _____ _. I believe the students can work it out .

Have you read the poems ______ by Du Fu —Of course, many of them.

Can your uncle play basketball—Yes, he can play ______ basketball ______ football. He is good at sports.