I can't help it

I can't help it—I always feel nervous before a big presentation, no matter how prepared I am.我控制不住自己——不管准备得多么充分，在大型演讲前我总是会感到紧张。

She can't help worrying about the launch; she's been working on it for over a year.她忍不住为产品发布感到担忧；她已经为此忙了一年多了。