第一句：I'm going back to China tomorrow.

　　我明天回中国。

　　A: Did you enjoy the trip?

　　这趟旅行玩得愉快吗？

　　B: I really enjoyed the trip. By the way, I'm going back to China tomorrow.

　　这趟旅行真的很愉快。顺便说一下，我明天回中国。

　　A: Oh, can't you stay longer?

　　哦，不能多呆一段时间吗？

　　第二句：When are you off?

　　您什么时候离开？

　　A: Hello, Mr. Xue. I've come to say goodbye.

　　您好，薛先生，我是来和您道别的。

　　B: You are leaving so soon? When are you off?

　　您这么快就要走了？您什么时候离开？

　　A: Early tomorrow morning.

　　明天一大早。

　　旅行结束返程时可向当地认识的朋友道别，说明自己回国的时间等，相关的表达法还有：

　　I am returning to Japan tomorrow.

　　我明天回日本。

　　I have to be going now.

　　我要告辞了。

　　Well, I must be off now.

　　嗯，我必须回去了。