357　can't help doing sth.和can't help but do sth.

　can't help doing sth. 是正确说法，意为“不禁……，不由得……”，在这层意思上不能说can't help to do sth.。这种结构中的help不表示“帮助”。can't help but do sth. 表示“只能做……”。

He couldn't help laughing when he heard her words. 听到她的话，他不由得大笑起来。

Whenever I see the photo, I can't help thinking of my childhood. 每当我看到照片，我都不禁想起童年。

They couldn't help but respect him. 他们不由得对他充满敬佩之情。

It is raining hard outside, and if you go out, you can't help but get your shoes wet. 外面正下着大雨，你如果出去，鞋子一定会弄湿的。

She can't help crying . （正）她不禁哭了起来 。

She can't help to cry . （误）