非谓语动词中itwhichthat有什么区别，都是在什么时候用

非谓语动词中itwhichthat有什么区别，都是在什么时候用？

这三个都不是非谓语动词。这三个都是代词。it是第三人称代词。which是疑问性指示代词。that是指示代词。非谓语动词是指在句子中不是谓语的动词，主要包括不定式、动名词和分词（现在分词和过去分词），即动词的非谓语形式。非谓语动词除了不能独立作谓语外，可以承担句子的其他成分。在句子中充当除谓语以外的各种句子成分的动词形式，叫做非谓语动词(the Non-Finite Verbs)。非谓语动词也是动词的一种，他们有着动词的其他特点，可以充当主语、宾语、状语等。非谓语动词与谓语动词是相对的概念。动词不定式动词不定式：（to）+ do，具有名词、形容词、副词的特征。否定式：not + (to) do以do为例，动词不定式的构成如下：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。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。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：不定式的句法功能：（1）作主语：To finish the work in ten minutes is very hard. 十分钟之内完成这项工作是很难的。To lose your heart means failure. 灰心意味着失败。动词不定式短语作主语时，常用it作形式主语，真正的主语不定式置于句后，例如上面两句可用如下形式：It is very hard to finish the work in ten minutes. 十分钟之内完成这项工作是很难的。It means failure to lose your heart. 灰心意味着失败。常用句式有：1、It+be+名词+to do。2、It takes sb.+some time+to do。3、It+be+形容词+of sb +to do。常用careless,,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise,等表示赞扬或批评的形容词，不定式前的sb.可作其逻辑主语。2．作表语：Her job is to clean the hall. 她的工作是打扫大厅。He appears to have caught a cold. 他似乎感冒了。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. 马克思发现研究俄国的情况是很重要的。动词不定式也可充当介词宾语，如：I have no choice but to stay here. 我只能留在这里，别无选择。He did nothing last Sunday but repair his bike. 他上周日除了修他的自行车什么也没干。动词不定式前有时可与疑问词连用，如：He gave us some advice on how to learn English. 他给了我们一些学英语的建议。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.此外，介词有时也与这种复合宾语连用，如：With a lot of work to do,he didn't go to the cinema． 他有很多工作要做，所以没去电影院。有些动词如make,let,see,watch,hear,feel,have等与不带有to的不定式连用，但改为被动语态时，不定式要加to,如：I saw him cross the road. 我看见他横过公路。He was seen to cross the road. 他被我看见横过公路。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. 我有一个会议要出席。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. 他找到了一个居住的好房子。The child has nothing to worry about. 这个孩子无忧无虑。What did you open it with? 你用什么打开它？如果不定式修饰time,place,way，可以省略介词：He has no place to live. 他无处安身。This is the best way to work out this problem. 这是解决这个问题的最好办法。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? 你要送什么东西吗？Have you got anything to be sent? 你有什么东西需要送吗？②说明所修饰名词的内容：We have made a plan to finish the work. 我们制定了一个完成工作的计划。③被修饰名词是不定式逻辑主语：He is the first to get here. 他第一个来到这儿。6．作状语：①表目的：He worked day and night to get the money. 他夜以继日地工作来赚钱。She sold her hair to buy the watch chain. 她卖掉了自己的头发来买那条表链。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. 为了省钱，他使出了浑身解数。wrong：To learn English well,a dictionary is needed.right：To learn English well,he needs a dictionary. 为了学好英语，他需要一本词典。②表结果(往往是与预期愿望相反的结果 意料之外)：常放在never only后He arrived late only to find the train had gone. 他来晚了，只见火车已经走了。I visited him only to find him out. 我去拜访他，只见他出去了。③表原因：常放在形容词后面They were very sad to hear the news. 他们听到这条新闻非常伤心。④表程度：It's too dark for us to see anything. 太暗了，我们什么也看不见。The question is simple for him to answer. 这问题由他来回答是很简单的。7．作目的状语：既可以放在句首，也可以放在句尾To tell you the truth,I don't like the way he talked. 说实话，我不喜欢他讲话的方式。8．不定式的省略：保留to省略do动词。If you don't want to do it,you don't need to. 如果你不想做这件事，你就不必做。9．不定式的并列：第二个不定式可省略to。He wished to study medicine and become a doctor. 他希望学医并成为医生。不定式1． “to” 是不定式符号还是介词，下列短语中的to 都是介词。agree to object to close to,come to,lead to,refer to,equal to,familiar to,point to,thank to,devote to,next to,belong to,be used to,look forward to2． 带to 还是不带toI have no choice but to give inI cannot do anything but give inI saw him enter the classroom .（ 但是：He was seen to enter the classroom .）3． 动词不定式逻辑主语是由for 作为标记的。但是有时用of .区别：当使用for时，句中形容词修饰的是不定式；而用of时，句中形容词修饰逻辑主语。It’s necessary for you to study hard .（necessary 修饰 to study hard，表示学习努力是有必要的）It’s foolish of him to do it .（foolish 修饰逻辑主语him）与of 连用的形容词有：good,kind,nice,wise,clever,foolish,right,wrong,careful,careless,polite,…与for连用的通常是一些表示可能性、难易程度、必要性等含义的形容词：possible，impossible，easy，hard，difficult，necessary，…4．后接不定式作宾语的动词有：want,hope,wish,like,begin,try,need,forget,agree,know,promise,teach,refuse,help,arrange,dare,decide,determine,fail,manage,offer,prepare,continue,ask,mean,choose,expect etc.需要宾语补足语的动词不能用动词不定式直接做介词的宾语，而要用it做形式宾语。例如：通常不说We think to obey the laws is important . 而说We think it important to obey the laws .5.不定式作宾语补足语时省略to的情况：若不定式前的谓语动词是使役动词make，let，have（表示“让、使”）、感官动词see，watch，look at，observe， notice，hear，listen to， feel时，不定式符号to可以省略。这些动词亦可总结为口诀：“三使五看两听一感觉”。例如：Let's （to）go！走吧！He saw the thief （to）steal a lady’s cellphone.注：改为被动句时要把to还原，例如：The thief was seentosteal a lady’s cellphone.6．不定式的省略。下列短语中，如果意义明确，常常省略到to。want to,wish to,hope to,like to,hate to,plan to,try to,love to,have to,ought to,need to,used to,be able to7．不定式作定语，应注意两种关系：1）动宾关系：He has a lot of meeting to attend .Please lend me something to write with .He is looking for a room to liveHe is looking for a room to live in .He has no money and no placeto live ( in ) .I think the best way to travel ( by ) is on foot .There is no time to think ( about ) .2）主谓关系：She is always the last ( person) to speak at the meeting .----I’m going to the post office,for I have a letter to post . ( 逻辑主语是I )-------Thank you. But I have no letters to be posted now ( 逻辑主语不是I )7．不定式作状语，可以有以下几种意义：1） 原因He is lucky to get here on time .这种结构中常用的形容词有：happy,glad,delighted,pleased,sorry,eager,anxious . lucky,fortunate,proud,angry surprised,frightened,disappointed,ready,clever,foolish,worthy2) 目的He came to help me with my maths .3) 结果I hurried to get there only to find him out .The book is too hard for the boy to read .He is old enough to go to school .8 . 不定式作补足语I saw him play in the street just now .能跟不带to 的不定式作补足语的动词有：see,feel,hear,listen to,look at,watch,let,have make,observe,notice注： 当这些词为被动式时，不定式要带to,如：He was seen to play in the street just now.现在分词现在分词：现在分词既具有动词的一些特征，又具有形容词和副词的句法功能。现在分词的形式：否定式：not + 现在分词1．现在分词的主动语态：现在分词主动语态的一般式表示与谓语动词所表示的动作同时发生，完成式表示的动作在谓语动词所表示的动作之前发生，常作状语。例如：They went to the park,singing and talking. 他们边唱边说向公园走去。Having done his homework,he played basket-ball. 做完作业，他开始打篮球。2．现在分词的被动语态：一般式表示与谓语动词同时发生的被动的动作，完成式表示发生在谓语动词之前的被动的动作。The problem being discussed is very important. 正在被讨论的问题很重要。Having been told many times,the naughty boy made the same mistake.被告诉了好几遍，这个淘气的孩子又犯了同一个错误。现在分词的句法功能：作定语：现在分词作定语，当分词单独做定语时，放在所修饰的名词前；如果是分词短语做定语放在名词后。In the following years he worked even harder.在后来的几年中，他学习更努力了。The man speaking to the teacher is our monitor's father.正与老师谈话的那个人是我们班长的父亲。现在分词作定语相当于一个定语从句的句法功能，如：in the following years也可用in the years thatfollowed; the man speaking to the teacher可改为the man who is speaking to the teacher.现在分词作表语：The film being shown in the cinema is exciting. 正在这家上演的电影很棒。The present situation is inspiring. 当前的形势鼓舞人心。be + doing既可能表示现在进行时，也可能是现在分词做表语，它们的区别在于be + doing表示进行的动作是进行时，而表示特征时是系动词be与现在分词构成系表结构。作宾语补足语：如下动词后可跟现在分词作宾语补足语：see,watch,hear,feel,find,get,keep,notice,observe,listen to,look at,leave,catch等。例如：Can you hear her singing the song in the next room? 你能听见她在隔壁唱歌吗？He kept the car waiting at the gate. 他让小汽车在门口等着。现在分词作状语：①作时间状语：(While) Working in the factory,he was an advanced worker.在工厂工作时，他是一名先进工人。②作原因状语：Being a League member,he is always helping others. 由于是共青团员，他经常帮助他人。③作方式状语，表示伴随：He stayed at home,cleaning and washing. 他呆在家里，又擦又洗。④作条件状语：(If) Playing all day,you will waste your valuable time.要是整天玩，你就会浪费宝贵的时间。⑤作结果状语：He dropped the glass,breaking it into pieces. 他把杯子掉了，结果摔得粉碎。⑥作目的状语：He went swimming the other day. 几天前他去游泳了。⑦作让步状语：Though raining heavily,it cleared up very soon.虽然雨下得很大，但不久天就晴了。⑧与逻辑主语构成独立主格：I waiting for the bus,a bird fell on my head．我等汽车时，一只鸟落到我头上。All the tickets having been sold out,they went away disappointedly.所有的票已经卖光了，他们失望地离开了。Time permitting,we'll do another two exercises.如果时间允许，我们将做另两个练习。有时也可用with (without) +名词（代词宾格）+分词形式With the lights burning,he fell asleep. 他点着灯睡着了。⑨作独立成分：udging from(by) his appearance,he must be an actor.从外表看，他一定是个演员。Generally speaking,girls are more careful. 一般说来，女孩子更细心。过去分词过去分词只有一种形式：规则动词由动词原形加词尾-ed构成。不规则动词的过去分词没有统一的规则要求，要一一记住。过去分词作定语：Our class went on an organized trip last Monday. 上周一我们班开展了一次有组织的旅行。Those selected as committee members will attend the meeting. 当选为委员的人将出席这次会。注意当过去分词是单词时，一般用于名词前，如果是过去分词短语，就放在名词的后面。过去分词做定语相当于一个被动语态的定语从句。过去分词作表语：The window is broken. 窗户破了。They were frightened at the sad sight. 他们对眼前悲惨的景象感到很害怕。注意：be + 过去分词，如果表示状态是系表结构，如果表示被动的动作是被动语态。区别：The window is broken.（系表）The window was broken by the boy.（被动）有些过去分词是不及物动词构成的，不表示被动，只表示完成。如：boiled water（开水） fallen leaves（落叶）newly arrived goods（新到的货） the risen sun（升起的太阳）the changed world（变了的世界）这类过去分词有：gone,come,fallen,risen,changed,arrived,returned,passed等。过去分词作宾语补足语：I heard the song sung several times last week.上周我听见这首歌被唱了好几次。有时过去分词做with短语中的宾语补足语：With the work done,they went out to play. 工作做完了，他们出去玩去了。过去分词作状语：Praised by the neighbours,he became the pride of his parents.受到邻居们的表扬，他成为父母的骄傲。（表示原因）Once seen,it can never be forgotten.一旦它被看见，人们就忘不了。（表示时间）Given more time,I'll be able to do it better.如果给予更多的时间，我能做得更好。（表示条件）Though told of the danger,he still risked his life to save the boy.虽然被告之有危险，他仍然冒生命危险去救那个孩子。（表示让步）Filled with hopes and fears,he entered the cave. 心中充满了希望与恐惧，他走进山洞。