I know I should stop smoking—don't give me a lecture about it.

我知道我该戒烟，别再教训我了。

Stop smoking and munch right to help your body stay at a healthy weight.

戒烟和慢慢咀嚼可以帮助你保持健康体重。

You ought to stop smoking.

你应当戒烟。

Some people do gain weight after they stop smoking.

有些人戒烟后的确增加体重了。

He came in for help after his attempts to stop smoking by willpower alone failed.

他仅靠毅力戒烟失败后到这里来求助。