您好!以下句型对吗?如对,请举例说明异同.

1.help to do sth = help do sth 帮着做某事
如：Please help carry this heavy box.
= Please help to carry this heavy box.
请帮忙抬一下这个重盒子.
当然,如果是在被动语态中,则这个to不能省略.
2.单独的短语help doing sth是不存在的.
但是有：can't/couldn't help doing sth
= can't/couldn't help but do sth
= can't/couldn't stop doing sth
意思是“禁不住/忍不住做某事”
如：I can't help crying.
= I can't help but cry.
= I can't stop crying.
我禁不住/忍不住哭了.

help to do sth. = help do sth.
没有help doing sth. 的说法
let me help you carry the box.
let me help you to carry the box.

help一词后加动词不定式做宾补时一般省略to
help sb. (to)do sth,可以省略to但变成被动语态时要加to
she help me (to) learn English. to可省略
I am helped to learn English. to 必加
I can't help laughing.我禁不住大笑。这样的句子里可出现 help doing的形式