While some students ________ (stop) the traffic, I went to the teachers' office for help.

 用所给词的适当形式填空

When I was a small boy, I ________ (get) to know the earth ________ (move) around the sun.

You'd better ________ (go) out ________ (get) some water at once.

The worker ______ (repair) a radio at seven last night.

Your father ______ (pass) the post office when I saw him.

Tom ______ (play) the piano ([pi'nu] n. 钢琴)when the telephone rang.

Is he ________ (clean) the blackboard now?

Mr Green _______ (not live) there.

She always ________ (study) very hard．

It's cold here. We'd better _______ (put) on our coats.