听短文，选择。
（1）_________________ at a red light.
A. Let’s go    B. Stop and wait   C. Slow down and stop
（2）How does John come to school?
A. By bus.          B. By bike.            C. On foot.
（3）We _________ pay attention to the traffic lights.
A. shouldn’t        B. must              C. must not
（4）---Does Amy often come to school by bike?
---_______
A. Yes, she does.    B. No, she doesn’t.   C. Yes, she is.