1. 从所给出的句子中选出合适的完成对话。

A. We must be careful with fire. B. We mustn't play with matches at home. C. I can put out fires.      D. Are you afraid of fire? E. What mustn't we do in the forest, Mr Li?

Ann: Hi, Mr Li. Welcome to our school.
Mr Li: No, I'm not. I'm a fireman.Fire is dangerous (危险的).
Don't play with fire.
Amy: What mustn't we do at home, Mr Li?
Mr Li: We mustn't play near fires.
Tim:
Mr Li: We mustn't smoke in the forest.
Tim: OK. I understand. Thank you, Mr Li.