Question

could not help后接doing和to do的区别

Answer 1

主要的区别在于：

1. can’t help doing sth.表示“不得不、禁不住做某事”，
   例句We couldn't help laughing when we heard the funny story.

   He can't help crying when he hears the bad news.

   She couldn’t help smiling. 她禁不住笑了起来。
   She couldn’t help envying Helen. 她不由得不妒忌海伦。
   

2.  can’t help to do sth.表示“不能帮助做某事”,

   例句 I can't help (to) wash the dishes because I am busy preparing for the entrance exams.

    I can’t help to do it. 我不能帮忙做这事
   

Answer 2

主要的区别在于：

1.can’t help doing sth.表示“不得不、禁不住做某事”

He can't help crying when he hears the bad news.

听到坏消息，他禁不住哭了起来。

2.can’t help to do sth.表示“不能帮助做某事

I can’t help to do it. 

我不能帮忙做这事

Answer 3

could not help doing sth 忍不住做某事
could not help to do sth 不能帮忙做某事