环球教育托福频道：在英语中,不作句子谓语,而具有除谓语外其他语法功能的动词,叫做非谓语动词.非谓语动词有动词不定式;动名词;现在分词;过去分词。口语中很多时候需要非谓语动词的语法运用，但是大多数学生对于这个现象只是听过，但是使用起来却不知所以然。下面让我们看看例句，考生们可记住固定的使用格式，以便应对托福考试。

　　一、动词不定式：(to)+do, 具有名词、形容词、副词的特征。

　　1. 不定式的形式：

　　否定式：not + (to) do

　　(1)一般式：不定式的一般式所表示的动作与谓语动词动作同时发生或发生在谓语动词动作之后, 例如：I'm glad to meet you.

　　(2)进行式：不定式的进行式所表示的动作与谓语动词动作同时发生,例如：The boy pretended to be working hard.

　　(3)完成式：不定式的完成式表示的动作发生在谓语动词动作之前,例如：I regretted to have told a lie.

　　2.不定式的句法功能：

　　(1)作主语：

　　To finish the work in ten minutes is very hard.

　　动词不定式短语作主语时,常用it作形式主语,例如可用如下形式：

　　It is very hard to finish the work in ten minutes.

　　(2)作表语：

　　Her job is to clean the hall.

　　(3)作宾语：

　　常与不定式做宾语连用的动词有：want, hope, wish, offer, fail, plan, learn, pretend, refuse, manage, help, agree, promise, prefer, 如果不定式(宾语)后面有宾语补足语,则用it作形式宾语,真正的宾语(不定式)后置,放在宾语补足语后面,例如：

　　Marx found it important to study the situation in Russia.

　　(4)作宾语补足语：

　　在复合宾语中,动词不定式可充当宾语补足语,如下动词常跟这种复合宾语：want, wish, ask, tell, order, beg, permit, help, advise, persuade, allow, prepare, cause, force, call on, wait for, invite.

　　(5)作定语：

　　动词不定式作定语,放在所修饰的名词或代词后.与所修饰名词有如下关系：

　　①动宾关系：

　　I have a meeting to attend.

　　注意：不定式为不及物动词时,所修饰的名词如果是地点、工具等,应有必要的介词,如：

　　He found a good house to live in.

　　The child has nothing to worry about.

　　What did you open it with?

　　如果不定式修饰time, place, way,可以省略介词：

　　He has no place to live.

　　This is the best way to work out this problem.

　　如果不定式所修饰名词是不定式动作承受者,不定式可用主动式也可用被动式：

　　Have you got anything to send?

　　Have you got anything to be sent?

　　②说明所修饰名词的内容：

　　We have made a plan to finish the work.

　　③被修饰名词是不定式逻辑主语：

　　He is the first to get here.

　　(6)作状语：

　　①表目的：

　　He worked day and night to get the money.

　　She sold her hair to buy the watch chain.

　　注意不定式放句首时,逻辑主语与句子主语要一致：

　　wrong：To save money, every means has been tried.

　　right：To save money, he has tried every means.

　　wrong：To learn English well, a dictionary is needed.

　　right：To learn English well, he needs a dictionary.

　　②表结果：

　　He arrived late to find the train gone.

　　常用only放在不定式前表示强调：

　　I visited him only to find him out.

　　③表原因：

　　They were very sad to hear the news.

　　④表程度：

　　It's too dark for us to see anything.

　　The question is simple for him to answer.

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