It is fairly common in Africa for there______ a group of expert musicians surrounded by others who also join in the performances.

When does our class meeting begin?—Oh, it’s been _____ because of the sports meeting.

Here are some books for _____ sister and _____.

You should help the person who is ______. [ ]

Mr Wang is an excellent teacher. He is ______ to spend a lot of time explaining things to us.