① 释义不同:help doing与can't连用,意为忍不住/情不自禁去做某事;
help to do 意为帮助、援助。
② 用法不同:help (to) do sth实际上有时候to是省略掉的,用作help do sth。
help + doing 是与can't一起用的,用作can't help doing sth。容易与can't help doing混淆的是can't help to do,译为不能帮助做某事。
③ 例句:
(1)I can't lift this box — will you help me please? 译文:我举不动这个箱子,请你帮我一下好吗?
(2)I couldn't help crying.译文:我忍不住哭了。
(3)He can't help to do housework,for he is busy. 他由于忙不能帮助干家务。
———————————————— 感谢提问!—————————————————