根据对话内容，从方框中的六个选项中选出五个合适的句子补全对话。
Linda: Hello,  .  
Peter: I'm reading a book about the people's lives in the future.
Linda: Oh, it's interesting. What will the people's lives be in the future?  
Peter: Yes, I think so, but I hope not.
Linda: 
Peter: Because there won't be enough food, fuel and room for too many people on the earth!
Linda: That's true.  
Peter: It's too hard. But maybe people will have on space stations (空间站) on the moon and grow vegetables (种植蔬菜)there.
Linda:  . By the way, do you think everyone will speak the same language in the future?
Peter: I hope so. Then people in different countries will understand each other better.

A. Do you think there will be more people? B. But maybe people will live on the moon in the future. C. It's a good idea D. Why do you hope not? E. Where are you going to do ? F. what are you doing?