补全对话。从方框中选出适当的句子补全对话。A: Lucy, why are you going out

补全对话。从方框中选出适当的句子补全对话。
A: Lucy, why are you going out 小题1: ?
B: That’s the sound of a truck collecting rubbish.
A: Do you mean you have to take the rubbish to the truck?
B: Yes. You know 小题2: is our duty. We should help protect the environment.
A: I agree. 小题3: , we must do something around the neighbourhood.
B: Sure. It is our duty to keep the environment clean and tidy. If we make a contribution to protecting the environment, 小题4:
A: That’s right. We mush try our best to make our country more beautiful. So we should 小题5: to improve the environment.

A. taking care of the environment B. the world will become much more beautiful C. do something useful D. after hearing the music E. Wherever live