根据对话内容，在下面的空白处填入适当的词，使对话的意思完整与正确。每空一词。

A: You must be really excited about leaving for America tomorrow, Zhang Hua!

B: Yeah. But I'm a bit .

A: For what?

B: I don't know about the customs and  in America. Can you help me??

A: Of course. With my pleasure.

B: What rules do they have in America?

A: Well. You are supposed to there on time. It's impolite to arrive late, because American expect their guests to be on time.

B: What else?

A: After the meal, don't leave at once. When your friends seem to be, it's time to leave. Then the next day, call or write a thank you note to tell them  much you enjoyed the dinner.

B: I see. Your advice may help me a lot.

A: Have a good trip.

B: Thank you.