A Professor, I've handed in my paper. Did you read it? 教授，我的论文已经交了。你看了吗?

B Yes. You've done a good job. But there's one thing. You should narrow down your topic. 是的。你写得不错。但是有一个问题。你应该缩小你的话题。

A What about water pollution instead of pollution? 用“水污染”代替“污染”怎么样?

B Well done! 非常好!