what to do 等相似句型 急求回答

what to do 是说的要去做什么，翻译随前面 的人称。

比如He doesn't know what to do at this moment.
他不知道目前要做什么。

what I should do说的是我应该做什么。

how to do it 说的是如何去做这个事情，强调的是方法。

这三条都可以做主语，宾语，和表语。
主语：
What to do is the biggest problem now.
What I should do is to help others to solve their problems.
How to do it is the biggest problem now.

宾语：
My sister is vague about what to do next.
I am pretty confused now. Please tell me what I should do now.
The experts are trying hard to find out how to do it well.

表语:
What troubles him most is what to do.
What troubles me most is what I should do.
What troubles the scientist most is how to do it.

可以进行一定的互换，转换的时候注意人称变化，以及内容的区别。

仅供参考。

what to do
what i should do

差不多，第一个是去做什么，第二个则是表义务

how to do it IT是宾语！怎样去做 它！ 宾语绝对不能省！有HOW的时候！

what to do 做什么,将要做什么 强调做的内容
what i should do 我应该如何做 强调做