3)不定式做表语

　　一种情况为主语是不定式(表示条件);表语也是不定式(表示结果)：1.To see is to believe.2.To work means to earn a living.

　　另一种情况为主语是以aim，duty，hope，idea，job，plan，problem，purpose，thing，wish等名词为中心的短语，或以what引导的名词性从句，不定式表语对主语起补充说明作用;例如：1.His aim is to study abroad in the near future.2.The most important thing is to negotiate with them about the price.3.What I want to say is to forget all the unhappy experience.

　　4)不定式作定语

　　不定式结构作名词词组修饰语主要有三种类型：

　　第一种，被修饰的名词词组是不定式的逻辑宾语。例如：1.There was really nothing to fear.2.He gave me an interesting book to read.

　　如果不定式是不及物动词，后面就得加相应的介词。例如：1.Mary needs a friend to play with.2.That girl has nothing to worry about.3.They have a strict teacher to listen to.4.Although the film had been on for ten minutes，I still was not able to find a chair to sit on.

　　第二种，被修饰的名词词组是不定式的逻辑主语;例如：1.Have you got a key to unlock the door?2.The action to be taken is correct.3.There is nothing to be gained by pretending.

　　第三种，被修饰的名词词组是不定式的同位结构。这类名词通常是表示企图、努力、倾向、目的、愿望、is算、能力、意向等意义的名词：ability，attempt，effort，impulse，inclination，wish等。例如：1.Her daughter will make an even bigger effort to please her.2.I have no wishto quarrel withyou.3.Neither of them had any inclination to do business with Mary.

　　5)不定式作状语

　　不定式结构在句中作状语通常都能转换为限制性状语从句。

　　例如作原因状语：1.They are quite surprised to see the great changes taking place in the area.2.They are quite surprised because they see the great changes taking place in the area.3.He was lucky to arrive before dark.4.He was lucky because he arrived before dark.

　　作目的状语：1.She raised her voice to be heared better.2.She raised her voice so that she could heard better.3.We went via Heidelberg to miss the traffic jam.4.We went via Heidelberg so that we could miss the traffic jam.

　　作结果状语：1.The French football team played so successfully as to defeat the Brazilians.2.The French football team played so successfully that they even defeated the Brazilians.3.He got to the station only to be told the train had gone.4.He got to the station and was told that the train had gone.

　　3

　　不带to的不定式的使用

　　动词不定式通常带to，但在有些搭配中不带to，在另一些搭配中可带to可不带to。归纳起来，以下情况下使用不带to不定式：

　　1)在can/could，/may/might，will/would，shall/should，must，need，dare等情态动词之后，动词不定式不带to。

　　2)在表示感觉意义的动词，如see初中英语语法总结，feel，watch，notice，smell，hear，observe等后，或是表示“致使”意义的动词，如have，let，make等后，动词不定式不带to。例如：1.I often heard him say that he would study hard.2.I must have him see his own mistakes.

　　但是，当这类结构转换为被动语态时，后面的不带to不定式一般转换为带to不定式。

　　例如：1.He was often heard to say that he would study hard.2.After he had finished speaking，he was made to answer innumerable questions.

　　3)在动词help之后可用不带to的不定式，也可用带to的不定式。例如：1.Help the old lady(to)carry the heavy box.

　　4)在had better，would rather，may/might as well，rather than，can not but等搭配之后初中英语语法总结，动词不定式也不带to。例如：1.Unless you feel to ill to go out，I would rather not stay at home tonight.2.She could not but criticize his foolish behaviour.

　　5)在make do，make believe，let drop，1et fall，1et fly，let slip，let drive，let go off，hear say，hear tell，leave go of等固定搭配中，用不带to的动词不定式。例如：1.They let go of the rope.他们松开了绳子。2.John let fly a torrent of abuse at me.约翰朝我痛骂了一顿。3.I've heard tell of him.我听说过他。4.Some of the faculty were let go for lack of the students.由于生源不足，一些教职员工被解雇了。