选择合适的句子，补全对话。

A. Are you doing your homework? B. Let's go swimming C. Maybe it is going to Australia.  D. Then I want to throw the bottle into the sea.  E. Where is it going?

Alice: , Peter. 

Peter: Sorry, Alice. I'm busy.

Alice: ?

Peter: No, I'm writing a letter. I will put it in a bottle.

Alice: Sounds great! 

Peter: I don't know.

Alice: Wow, it's fun.