1.Please tell him to stop smoking.

请告诉他不要抽烟。

2.Please refrain from smoking.

请禁止吸烟。

3.This is the smoking section,isn't it?

这是吸烟区，不是吗？

4.I'd like to smoke.

我要吸烟。

5.I am a heavy smoker.

我是位老烟民。

6.Can I change my seat next to my friend's over there？

我可以把我的座位换到我朋友那边吗？

7.May I smoke?

我可以吸烟吗？

8.Do you mind if I smoke?

如果我吸烟，你介意吗？