1. 选择合适的提示语。

A. Take turns.       B. Keep your desk clean. C. Work quietly.        D. Talk quietly.          E. Keep to the right.

1. （1） We are waiting for a bus at the stop.
3. （2） She is talking aloud in the hospital.
5. （3） The students are going up and down the stairs (楼梯).
7. （4） They are doing their homework in the classroom.
9. （5） The boy is colouring at his desk.