从A-G选项中选出能填入空白处的最佳选项补全对话。（选项中有两项是多余的）

A. Would you please tell me  what to do as a guide?

B. What would you like to do?

C. How are you doing?

D. It will be held in your country, won't it?

E. Oh, congratulations!

F. It's very nice of you to tell me so much.

G. I'm afraid not.

A: Hi, Tongtong!

B: Hi, Bruce!  1._____  

A: Very well, thank you.

B: I know the 30th Olympic Games is coming next month. 2._____

A: Yes, that's right.

B: Will you go back to your hometown soon?

A: Of course. And I will be a guide during the Olympics.

B:  3._____  I was once a guide in the 2008 Beijing

Olympics, too.

A: Thank you! 4._____

B: Sure! We can help people to find their ways. Also, we can introduce the places

    of interest to the friends both at home and overseas.

A: Excellent! I hope to become a guide like you!  5._____ Thanks a lot!

B: You are welcome!

简述吸附过程的缺点？