根据实际情况回答问题。
【小题1】What should you do when you cross the road?
___________________________________________
【小题2】Can you cross the road on a yellow light?
___________________________________________
【小题3】Must you go to school on time?
___________________________________________
【小题4】If you see a boy running on the stairs, what will you say to him?
____________________________________________

补全句子
What _____ you do _____ you see an old lady standing on the bus?

If she a lot of chocolate every day, she will be very fat. (   )

A．is

B．has

C．have

D．be

补全句子
1._____people cut down the forests, animals 2._____ lose their home.

What if there is no rain? (   )

A．happen

B．is happing

C．will happen

D．happened