1. “cannot …too…”表示“无论怎么……也不（过分）”。 You cannot be too careful in crossing the street. 过马路越小心越好。 You cannot praise him too much. 你怎么表扬他都不过分。 I can never thank him enough. 我对他感激不尽。 2. “can’t help doing sth”表示“不禁，忍不住，不得不（做某事）” Hearing the news, I can’t help laughing. 3. “can’t help but do sth”表示“不禁，忍不住，不得不” I can’t help but be sorry about it. 我不能不为之感到遗憾。 I cannot help but admire her courage. 我情不自禁地钦佩她的勇气。 4. “cannot but do sth”表示“除此 之外，别无他法，”。 I couldn’t but laugh on his funny face. 看到他那张滑稽的脸，我只能笑了笑。