一、"疑問詞+不定式"的構(gòu)成：由疑問代詞who,whom,what,which; 疑問副詞when,how,where等+不定式構(gòu)成.
Choosing what to eat is no longer as easy as it once was.選擇吃什么,已經(jīng)不像以前那么簡(jiǎn)單了.
How to describe people is today's topic.如何描述人物是今天的話題.
二 、"疑問詞+不定式"的功能：在句中可作主語、賓語、表語等成分.
1.作主語
How to give advice in English is what I am trying to learn.我正在努力學(xué)習(xí)如何用英語提建議.
2.作賓語
①作動(dòng)詞的賓語
We have to start somewhere if we want to learn how to write plays.我們要學(xué)習(xí)寫劇本,總得有個(gè)開頭.
②作介詞的賓語
We had better learn to make the right choices about what and how we eat.我們最好能學(xué)會(huì)正確選擇吃什么、怎么吃.
When you are trying to advise someone about what to do or what not to do,you can use should / ought to or should not /ought not to.當(dāng)你想要建議某人做什么或者不做什么時(shí),你可以用should / ought to 或者 should not / ought not to.
3.作表語
My question is where to find the answer.我的問題是在哪里能找到答案.
三、"疑問詞+不定式"的使用方法.
⒈ "疑問詞+不定式"構(gòu)成的短語在句中當(dāng)"名詞"用,可以寫成相應(yīng)的從句.
I am not sure how to behave at the dinner table.(= I am not sure how I should behave at the dinner table.) 對(duì)餐桌禮儀,我心中沒底兒.
⒉ 這種結(jié)構(gòu)中,疑問代詞須接及物動(dòng)詞或相當(dāng)于及物動(dòng)詞的短語(who,which除外)
疑問代詞須接及物動(dòng)詞或相當(dāng)于及物動(dòng)詞的短語
【誤】 I don't know what to talk.
【正】 I don't know what to talk about.
但可以說：We haven't decided who (which) to go.我們還沒定誰(哪個(gè))去.
⒊ 這種結(jié)構(gòu)中的疑問副詞后要接不及物動(dòng)詞；若接及物動(dòng)詞,要有動(dòng)詞的賓語.
疑問副詞后要接不及物動(dòng)詞；若要接及物動(dòng)詞,要有動(dòng)詞的賓語
I don't know how to talk.我不知如何談.
I wonder if you could tell me how to do it.不知您能否告訴我如何去做這件事.(不能說:...how to do.)
多留心一些類似的句子,自然而然就容易記住了.這種結(jié)構(gòu)中，疑問代詞須接及物動(dòng)詞或相當(dāng)于及物動(dòng)詞的短語(who, which除外)疑問代詞須接及物動(dòng)詞或相當(dāng)于及物動(dòng)詞的短語【誤】 I don't know what to talk. 【正】 I don't know what to talk about.沒看懂。。。因?yàn)閠alk是不及物動(dòng)詞，所以必須要加上介詞about。再比如 He buys a house to live in.因?yàn)閘ive是不及物動(dòng)詞，in不能少是不及物動(dòng)詞，后面就必須要跟介詞嗎，那arrive呢？不是說必須接介詞，而是不能直接帶賓語，要想帶賓語，必須加介詞arrive 后要想加地點(diǎn)的話，必須加at 或in