讲一讲2 wh-+ to do sth.

​讲一讲2  wh-+ to do

“疑问词+不定式”结构

“疑问词+不定式(短语)”是一个很有用的结构，通常可称之为不定式的复合结构，它的作用相当于一个名词性从句，通常在某些动词, 如tell, know, imagine, learn, decided, forget, remember, consider, understand等后面做宾语，也用作主语、表语、同位语：　　

1.作主语

When for us to start has not been decided. 

It hasn’t been decided when we should start.

我们何时动身尚未决定。　　

2.作宾语

He didn’t know how to answer her. 

He didn’t know how he should answer her. 

他不知道该怎样回答她。　　

I don’t know who to ask advice from. 

I don’t know I should ask advice from whom.

我不知道应向谁征求意见。　　

Would you please advise me which to buy? 

Would you please advise which I should buy?

你能否告诉我该买哪一个才好?　　

Please explain (to me) where to begin and how to do it. 

Please explain (to me) where I should begin and how to do it. 

请 (给我)解释该从哪里开始及该怎么做。　　

They exchanged views on the question of whom to elect. 

They exchanged views on the question whom they should elect. 

他们就该选谁的问题交换了意见。　　

3.作表语

The question is where to make a discussion.

问题是该在哪里进行讨论。

The puzzle remains how to deal with the tough problem.     

困惑的是如何解决这个棘手的问题。

4.作同位语

All of a sudden, the crowd fell silent at a loss what to do next.

All of a sudden, the crowd fell silent and were lost in thought of what they          should do next.

突然间，人群沉默了，不知道下一步该怎么办。

On a second thought who to turn to for help, they agreed to set off shortly.

They thought twice who they should turn to for help and agreed to set off shortly.      再三考虑该向谁求助，他们同意了马上出发。

注意：按英语习惯，疑问词why后面通常不接不定式。但在以why或why not 开头的省略型疑问句中，其后可跟不带to 的不定式，表示建议：　　

Why get upset just because you got a bad mark? 

何必因为没有考好就想不开呢?　　

You’re looking tired. Why not take a rest? 

你一脸倦容，怎么不休息呢?