You can feel something cooling off right. I mean simple examples of these happen when you you know, if you buy cold or hot packs.

可以立即反应的东西,你可以感到有的东西会冷却，对吧？,我是说，举个简单的例子。

麻省理工公开课 - 热力学与动力学课程节选

You use "I can't help but" when you feel helpless, when you want to get something across that needs to happen.

当你觉得无助时，或者当你说明需要做到这件事情的时候，你就可以使用“I can't help but”句型。

I can't help but 课堂 - SpeakingMax英语口语达人