英语语法精讲：“疑问词+不定式动词”结构

英语自学网

　　英语有个很有用的结构，就是：疑问词+不定式动词(question word + to-infinitive)。
        　　疑问词是疑问代词“who, whom, what, which, whose”和疑问副词“when, where, how, why
”。此外，连接词“whether”也适用。
        　　“疑问词+不定式动词”结构有何功用呢?其主要功用有下列五种：
        　　⑴当主语，如：
        　　● When to hold the meeting has not yet been decided.
        　　● Where to live is a problem.
        　　● How to cope with the rising cost of living becomes a daily discussion
topic.
        　　⑵当宾语，如：
        　　● We must know what to say at a meeting.
        　　● He could not tell whom to trust.
        　　● Do you know how to play bridge?
        　　⑶当补足语，如：
        　　● The problem is where to find the financial aid.
        　　● The question is who to elect.
        　　⑷当名词同位语，如：
        　　● Tom had no idea which book to read first.
        　　● Do you have a rough impression how to do it?
        　　⑸当宾语补足语，如：
        　　● Jim is not sure whose to choose.
        　　● Mary and John are not certain whether to get married or not.
        　　适用于“疑问词+不定式动词”的动词包括：“know, see, decide, tell, ask, consider, discover,
explain, forget, guess, hear, imagine, inquire, learn, remember, think, wonder,
understand”等。
        　　有点值得特别注意的是：当这结构当宾语时，它的作用等于名词分句，例如：
        　　● I could not decide which dictonary to buy. / I could not decide which
dictionary I should buy.
        　　● Jack did not know where to find such a good teacher./ Jack did not know
where he could find such a good teacher.
        　　有些动词，如“ask, show, tell, advise, inform,
teach”等，可以先有个宾语，然后才接着加上适当的“疑问词+不定式动词” 结构。例如：
        　　● The chief technician showed the apprentice how to repair the machine.
        　　● Have you told him where to get the application form?
        　　综上所述，可见“疑问词+不定式动词”结构是个形象清新，既容易用又不容易出错的特别结构，可以多多运用。