从方框中选择正确的句子补全对话。

David: Hi, Sam.

Sam: Hi, David. I am going fishing.

David:  But there are some dark clouds in the sky. It's going to rain soon.

Sam:  It's a beautiful day. Do you want to go with me?

David:

Sam: Why?

David:

Sam: What a good boy!

A. Because I'm going to help my mum clean the room. B. What are you going to do this afternoon? C. No, I don't. D. That sounds great. E. I don't think so.