根据上下文补全对话，在横线上写出所缺少的内容。
A: Excuse me. Is there a post office near here?
B: I'm sorry, I don't know. You can ask this policeman, I think.
A: 1. ____________________________. Excuse me, sir. I need your help.
C: Are you looking for the nearest post office?
A: Yes.
C: 2.__________________________________________________, turn left at the second crossing, and walk
on to the end. The post office is on the right.
A: 3.________________________________________________________?
C: It's about two kilometers away. You can also take a bus.
A: 4.________________________________________________________?
C: No. 5 bus. The bus stop is over there, on the other side of the street.
A: Thank you very much.
C: 5.________________________________________________________
