Y: I'm sorry I'm late.

　　Y:真抱歉，我迟到了。

　　X: Oh, that's all right. I just wondered what was keeping you.

　　X:哦，没关系。我刚才还在想什么事把你耽搁了。

　　Y: The bus I took.

　　Y:是我乘的公交车把我耽搁了。

　　X: What do you mean?

　　X:怎么讲呢?

　　Y: I took the wrong bus.

　　Y:我乘错车了。

　　X: Oh, did you? That's very easy to do.

　　X:哦，这样啊?那是常有的事。