非谓语动词todo的用法小结
非谓语动词不定式（to do）的用法小结I．不定式的语法意义
1.不定式具有名词、形容词、副词的特征，在句中可作主、宾、定、表、补和状语。
2.没有人称和数的变化，在句子中不能作谓语，但有时态和语态的变化。
3.仍保留动词的特征，即可有自己的宾语和状语，和他们一起构成不定式短语。
II. 不定式的否定式
not to do
III.不定式的时态和语态
1.一般式（to do/to be done）表示动作或状态与谓语动词的动作或状态同时发生或发生在其后。
2.完成式（to have done/to have been done）表示动作或状态在谓语动词的动作或状态之前。
3.进行式（to be doing）表示动作谓语动词所表示的动作或状态发生时正在发生。
大枣的营养价值4.完成进行式（to have been doing）表示在谓语动词的动作或状态发生之前开始进行的行为，到谓语动作发生时，可能停止，
也可能会持续下去。
IV．不定式的功能
1.作主语：
（1）to do可直接作主语，表示
爆肉特指一个具体动作。
eg.To swim in that river is very dangerous.
To study English well isn’teasy.
(2) 用it作为形式主语，而把真正的不定式主语放到句中。常见的有6种。
It is +adj+ to do sth.
eg.It is nice not to be dependent onothers.
It is +adj+for sb to do sth.
eg.It is not hard for one to do a bit of good
It is +adj+of sb to do sth.
eg. It is silly of you to believe him.
三星台式电脑= You are silly to believe him.
It is +noun+to do sth.
eg.It was not his habit to ask people for things.
It+动词（+宾语）+ to do sth.
eg.It took me a year to finish writing the
book.
It is+介词短语+to do sth.
eg.It is beyond my power to answer this question.
2.作表语：to do作表语很普遍，多数情况下可换作主语
eg.Her job is to teach us maths.
To teach us maths is her job.
3.作宾语：to do作宾语直接跟在vt 动词后面。这些vt 动词的口诀是：
答保要打假希期，（14）
设宣申负愿花力。（7）
提安同学准声敢，（7）
偏威三决拒恳企。（8）
依照本口诀可写出下列36个vt 动词。promi答应，connt答应，guarantee保证，pledge保证，demand、ask要求，ai m/mean 打算pretend、profess假装wish、hope希望expect、desire期望
manage设法，swear宣誓，apply申请undertake负责，care愿意，can afford(花、买)得起， endeavour力图
offer提供，arrange安排，agree同意，learn 学习，prepare准备，claim声称，dare敢choo偏要、宁愿，threaten威胁，determine、resolve、decide决定，refu拒绝，beg恳求，ek企图或用“UBRT-wolf-head-maps”口诀。
eg. I want to buy a car.
They wish to e you.
注意：有些vt用to do 和doing作宾语意义区别不大，但在下列情况有别
(1)begin、start只用to do
be beginning/starting to do
begin/start+认知动词
eg.She was beginning to work on her novel that summer.
He began to realize that he was wrong. (2)remember/forget/regret+ to do(未做) remember/forget/regret+doing(已做)
eg.I remembered returning his money.
(3)try to do(努力做)
try doing(试着
4．作定语：to do 作定语与修饰的名词
出存在一种动宾关系、主谓关系或说明关系。
eg. They have no room to live in.
He found an opportunity to go there.
Energy is the ability to do work.
5.作宾补、主补：to do在主动语态中为宾补、在被动语态中为主补。补语与宾语在逻辑上存在着主谓关系，多数动词要带to,遇到使动词、感观动词则不带to,比如（make、let、e、hear、watch、feel、notice、obrve）但若为动语态则还原to.
eg.They ask us to sing a song
课程观
I heard him knock at the door twice.
Tom was made to work 12 hours a day.
5.作状语：to do作状语多在vi后表目的或结果，作目的还可置句首，同时还可在某些形容词后作状语
eg. John came to study Chine.
I am glad to e you.
He lifted a stone only to drop it on his own feet.
干煸牛肉的做法
V．不定式符号to的省略
1.在助动词、情态动词后（had to,ud to,ought to,be able to除外，因它们本身带to.
2.在had better,would rather…than…,rather than,do nothing other than,might as well(不妨，还是….的好，can’t help but/can’t choo but/cannot but(不得不)
3.在介词but /except/besides前有do的各种形式时。
eg.I could do nothing but wait for him here. 4.当help后面跟不定作宾语或作宾补时，不定式符号to用与不用都可以，但当主语是表示物的名词或主语不能发出不定式的动作时需要带to.
削铁如泥
eg.This book helped me toe the truth.
5在祈使句中
eg.Sit down ,plea.
感恩父母的歌曲6.在why not 或why引起的疑问句中，否定表建议，肯定表不满或委婉批评。
eg.Why not go out for a walk.
Why stand up if you can sit down.
7如果两个或两个以上具有同样功能的不定式并列第一个有to，其余无to.
eg.His wish is to enter this college and study English.
8.动词need/dare
(1)情态动词后无to
(2)实意动词肯定形式有to
(3) 实意动词否定、疑问式可有可无to eg. I need to buy a bike.
You didn’t need (to) try.
Does she dare( to) go out at night?
9.当不定式作表语时，如果句子的主语是all 或what引导从句或主语被only,first,one,least 及adj最高级修饰，且后面的从句或短语中有实意动词do 时,作表语的不定式可不用to. eg.The only thing I can do is(to) stay at home.
一望
