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1、it用法完全归纳一、it 作人称代词的用法1. 指事物作为人称代词，it 可以指代除人以外的一切事物或动物。如：I dropped my watch and it broke. 我把手表掉在地上摔坏了。Its hard work, but I enjoy it. 工作很辛苦，可是我乐意干。“Where is the dog?” “Its in the bedroom. ” “狗在哪?”“在卧室里”。2. 指人it 指人主要用于指性别不明的婴儿或用于确认某人的身份。如：Is it a boy or a girl? 是男孩还是女孩?There is a knock on the door. It
2、must be the postman. 有人在敲门，一定是邮递员。【说明】在答语中，常用来指本人，如说 Its me.3. 代替某些代词代词 it 还可用于代替指示代词this, that 以及复合不定代词 something, anything, nothing等。如：“Whats this?” “Its a new machine. ” “这是什么?”“是一种新机器”。Nothing is wrong, is it? 没出什么问题，是吗?二、it 作非人称代词的用法1. 基本用法it 作非人称代词的用法，主要用于指时间、距离、价值、天气、气候及温度等自然现象。如：Its too late
3、 to go there now. 现在去那儿已经太迟了。It rained all day yesterday. 昨天下了一天的雨。It can get very hot here. 这里有时会很热。2. 用于某些句型Its time for sth. 该做某事了。Its time to do sth. 该做某事的时候了。Its time for sb to do sth. 某人该干某事了。Its (about / high) time + that-从句. 某人该做某事了。(从句谓语用过去式，有时也用“should+动词原形”)Its first (second) time + that-
4、从句. 某人第几次干某事。(从句谓语用现在完成时)Itis/hasbeen一段时间since从句。意为“自以来已有多长时间了”或“自不以来已有多长时间了”。例如：IthasbeenmanyyearssinceIwaslastinLondon.自从我上次到伦敦，已经有许多年了。2）Its + 时间段 + before-从句. 过多长的时间才Itsalongtimesincewemetlast.自从我们上次见面以来已经有很长一段时间了。3）-Whatwasthepartylike？-Wonderful！Itsyears_IenjoyedmyselfsomuchAafterBbeforeCwhenD
5、since(key:D)2、Itis/was/willbe+一段时间+before从句。表示“在（做某事）前过了多长时间”，或“过了多长时间才”。如：Butitwillbemorethan100yearsbeforethecountrybeginsonceagaintolookasitdidbefore.但是在100年之后，这个国家才能恢复到以前的样子。三、it用作形式主语1. 基本用法当不定式、动名词、从句等复杂成分用作句子主语时，为保持句子平衡，通常把真正的主语放在句末，而在句首使用形式主语it。如：Its very important to remember this. 记住这一点很重要
6、。Its hard work climbing mountains. 爬山是费劲的事。Its unknown when he will come. 他什么时候来还不知道。2. 用作形式主语的的重要句型(1) It + be + adj. for (of) sb to do sth 某人做某事It is hard for him to make up his mind. 他很难下定决心。It was foolish of her to say such a thing. 她说那样的话，真是太蠢了。【说明】该句型中的形容词通常是表示事物的特点或特征的如difficult，hard，easy，imp
7、ossible，necessary，important等，此时用for；或表示人的性格特征或特点的如nice，good，bad，kind，silly，foolish，wise，clever， careless，rude，brave，cruel，careful， grateful等，这时要用 of。如：1）Is _ possible to fly to the moon in a spaceship? (nmet 88) A. now B. man C. that D. it (key: D)2）Is _ necessary to tell his father everything? (nme
8、t 89) A. it B. that C. what D. he (key: A)3) In fact _ is a hard job for the police to keep order in an important football match. (上海 2001) A. this B. that C. there D. it (key: D)介词 of 与 for 的区别是：of 用于指某人的性格、属性、特征等，介词for表示对象，意为“对来说” .(2) It takes sb + 时间段 + to do sth. 做某事花了某人时间It takes years to mast
9、er a new language. 要花多年的时间才能掌握一门新的语言。【说明】此句型可以有以下多变种变体：It took me an hour to write the letter. =The letter took me an hour (to write). =I took an hour to write the letter. 我写这封信花了一个小时。(3) It is up to sb to do sth. 该由某人做某事Its up to you to make the choice. 得由你来作选择。(4) It look (seem, appear, happen, oc
10、cur) that as if 似乎It seemed as though he didnt recognize me. 他似乎没认出我来。It happened that I was out when he called. 他打电话时我碰巧不在家。(5) If it were not for / If it hadnt been for 若不是因为If it were not for their help, we couldnt have got over the difficulties. 要不是他们帮助，这些困难我们不克服不了的。2、It + be + fun/ a waste of t
11、ime/ no good/ no use doing sth.1）It is no use crying over spilt milk. 谚 牛奶已泼，哭也无用。注：偶尔也可以将动名词用成不定式。如2）It is no good to read without full understanding. 没有完全理解的阅读是无用的。3、It be过去分词that从句. 适用该句型的过去分词主要有 said, reported, announced, hoped, thought，told，believed，expected，decided，suggested, known等。该句型常可以转换成含
12、有宾语从句的复合句.如：1）They are said to be very good. 据说他们都很棒。It is said that they are good.2）it is hoped that one day they will have enough animals to set them free 人们希望有一天能有足够的麋鹿可以放出去4、It be形容词 that从句。可用于此句型的形容词还有wonderful， true，good，right，wrong，（un）important ，useless，surprising，clear，unusual，lucky，certain
13、等。 如：1）It is quite certain that will be at the meeting. 他当然回出席会议。2）It is important that we (should) study hard. 我们应该努力学习，这是很重要的。5、It be名词（词组）that从句。适用该句型的名词（词组）还有a pity，an honor，a good thing，a fact，a surprise，good news等。 如：1).It is a pity (that) you missed the sports meeting last week. 你错过了上周的运动会，真遗
14、憾。2)._ is a fact that English is being accepted as an international language. A. there B. this C. that D. it (key: D)6、it seem appear happen的适当形式that从句。该句型常可以转换成含不定式的简单句。如：1) It seems that there is a big waste pipe coming down from the town.There seems to be a big waste pipe coming down from the tow
15、n.2) He appeared calm, but inside his heart was beating wildly with fear. It appeared that he was calm, but inside his heart was beating wildly with fear.7、It doesnt matter（its no wonder；it doesnt make too much difference等） when/ where/ which/ whether 等从句。 如：1）Does _ matter if he cant finish the job
16、 on time?(nmet 91)A. this B. that C. he D. it (key: D)2) They are all classmates_ is no wonder _ they should help each other with their studies（上海 98） Athis；whether Bit；if Cthat；that Dit；that （key: D）四、it用作形式宾语1. 基本用法当不定式、动名词、从句等复杂成分用作宾语且其后跟有宾语补足语时，通常会在宾语补足语前使用形式宾语，而将真正的宾语移至句末。其基本结构为“s. + v. it + ad
17、j. / n./ + 不定式或从句”。常用于这一句型的动词有 find, consider, feel, make, think 等。如：I find it difficult to do the job well. 我发现做好这件事不容易。I think it best that you should stay here. 我认为你最好住这儿。We think it no use complaining. 我们认为抱怨是没有用的。I feel it our duty to study English well. 我认为学好英语是我们的职责。4)I dont think _ possible
18、to master a foreign language without much memory work. A. this B. that C. its D. it (key: D) 2. 用作形式宾语的几个特殊结构(1) 动词+ it + that-从句。如：I like it that you came. 你来了，我很高兴。I take it (that) he will come on time. 我认为他会准时来的。You can put it that it was arranged before. 你可以说这是以前安排的。Rumor has it that the defence
19、 minister will soon resign. 据传闻，国防部长不久就要辞职。【说明】能用于此结构的动词不多，常见的有 have, take, put, like 等。(2) 动词 + it + when (if)-从句。如：I dislike it when you whistle. 我不爱听你吹口哨。We really appreciate it when she offered to help. 她来帮忙了，我们十分感激。Id prefer it if I didnt have to do so much work. 要是我不必做那么多工作，好就太好了。【说明】能用于此结构的动词
20、不多，常见的有 enjoy, hate, love, like, dislike, appreciate, prefer 等。(3) 动词 + prep + it + that-从句。如：See to it that youre not late again. 注意千万不要再迟到。Look to it that this doesnt happen again. 注意不要再发生这种事。You may rely on it that hell come to meet you. 你放心，他会来接你的。I cant answer for it that he will come. 我不能保证他会来
21、。【说明】能用于此结构的动词不多，常见的有see to, look to, insist on, stick to, depend on, answer for 等。(4) 动词 + it + 介词短语+ that-从句。如：I owe it to you that I am still alive. 多亏有你我才仍然活着。I took it for granted that he would help us. 我认为他会帮助我们的。【说明】能用于此结构的动词不多，常见的有take it for granted, bring it to sbs attention, owe it to sb
22、等。五、在一些相对固定的词组中出现，没有特殊含义，经常不翻译。如： 1. Hes never really made it as an actor. 作为演员，他从未获得过真正的成功。2.It is my turn 轮到我了。3. Thats just it-i cant work when youre making so much noise. (oxford) 原因就在这儿-你们这么吵，我没法工作。8、s. + v. it + adj. / n./ + 不定式或从句。常用于这一句型的动词有 find, consider, feel, make, think 等。如：1) He found
23、it important to study the situation in Russia, 他发现研究俄国形势非常重要, 2） I want to make it clear whether she is still at school. 我想弄清楚她是不是还在上学。3) I feel it our duty to study English well. 我认为学好英语是我们的职责。4) I dont think _ possible to master a foreign language without much memory work. A. this B. that C. its D
24、. it (key:D) 六、it 用来引起强调句型句型结构为：it iswas 被强调部分thatwho其它。分析和使用该句型时应该注意以下几点：1) . 可以强调主语、宾语或状语；it本身没有词义，只用来构成这个句型；指现在用is, 指过去用was; that可以指物，也可以指人，who只用来指人，偶尔也用whom指人（强调宾语时）。 Yesterday he met an old friend in the park. 强调主语： It was he that/who met an old friend in the park yesterday. 强调宾语： It was an old
25、 friend that/who he met in the park yesterday. 强调时间状语： It was yesterday that he met an old friend in the park. 强调地点状语： It was in the park that he met an old friend yesterday. 2) . 强调句型的基础知识： . 强调地点状语不用where，时间状语不用when，方式状语不用how，原因状语不用why，都要用that. It was for this reason that he left that school. (原因状
26、语) It was in this way that he solved the problem. （方式状语） . 也可以是状语从句被强调： It was only when I reread his poems that I began to appreciate their beauty.时间状语） It was because she got up late that she didnt catch the first bus. （原因状语从句） . 被强调部分如果是原句的主语，who/that后的谓语在人称和数上应和原句的主语一致。 It is Mary who often does
27、 good deeds. Ability is what youre capable of doing.Motivation determines what you do. Attitude determines how well you do it. 强调句型可以是个否定句： It was not I that met your father in the street. . 判断一个句子是否是强调句的方法： 如果将句中的It is/wasthat/who去掉，经整理后还是一个完整的句子，本句就是强调句，否则，就不是。 It was in todays newspaper that we f
28、ound the news. We found the news in todays newspaper. (句子意思完整，所以上句是强调句) . 强调一般疑问句中的某一个成分时，要用一般疑问句的语序，把is/was提前。 Did this happen in Beijing ? Was it in Beijing that this happened ? Wasnt it he that had made a mistake ? . 特殊疑问句只有疑问词可以强调： 疑问词+is/was it +that-clause ? Where were you born ? Where was it
29、that you were born ? . 强调句型的系动词除了用is/was外，还可以在其前面加上may/might/must等表示推测的情态动词。 It might be him that you met yesterday. . 在被强调的部分后接定语从句，使句子结构更加复杂。 It was in Beihai Park _ they made a date for the first time _ the old couple told us their love story. A. where, that B. that, that C. where, when D. that,
30、when 选A.第一个空后是定语从句，缺地点状语，用where, 第二个空才是强调句型的that. 又如：It was on July 7th, 1975 when he was born that his father died. 4. not.until.的强调句型： It is / was not until 时间状语 that-clause Not until+时间状语+（主句的）倒装句 5. I didnt realize she was a film star until she took off her dark glass. It was not until she took
31、off her dark glasses that I realized she was a film star. Not until she took off her dark glasses did I realize she was a film star. 注意：此句型只用until，不用till。但如果不是强调句型，till和until可通用。因为句型中It is / was not.已经是否定句了，that后面的从句要用肯定句，切勿再用否定句。5、强调句型的两种变形形式：一般疑问句形式：is/ was it that? 特殊疑问句形式：who/ whom /when/ when 等
32、 + is/ was it that ? 如：1)Was it in 1979 _ the American astronaut succeeded _ landing on the moon? (上海 94)A. when; on B. that; on C. when; in D. that; in (key: D)2）Was _ that i saw last night at the concert? A. it you B. not you C. you D. that yourself (key: A)3）Who was it that you met in the street
33、yesterday? 昨天你在街上遇到的是谁？Where was it that you met jack yesterday? 你昨天是在哪里遇到杰克的？6、当强调的成分是表示时间或地点的介词短语时，如果去掉介词，句型会发生根本变化。试比较：It was five oclock in the afternoon _ they climbed up to the top of the mountain Asince Bwhen Cthat Duntil (key:B)该句为 when 所引导的时间状语从句，it 在句中表示时间。如在题干上加上介词 at，句子变成：it was at five
34、oclock in the afternoon _ they climbed up to the top of the mountain空格中只能填 that，为强调句。因为：高考原题目如果填 that，就应该是强调句，去掉 it，was，that，可以得到：they climbed up to the top of the mountain five oclock in the afternoon. （不成立）所以高考原题不能填 that；而增加介词的句子可以改写为： they climbed up to the top of the mountain at five oclock in t
35、he afternoon. 这是个完整的句子，所以填 that，为强调句。七、另外两个与it 有关的常用句型1、Itiswaswillbethe+序数词+timethat从句。该句型意为“这是那是这将是某人第某某次做某事了”。主句谓语动词用is时，从句用现在完成时；主句的谓语动词用was时，从句用过去完成时；主句的谓语动词用willbe时，从句的谓语动词用一般现在时表示将来。如：1)sheunderstoodwhatIwastalkingabout,eventhoughitwasthefirsttimewehadspokentogether. 尽管这是我们第一次在一起谈话，但是她明白我们在谈些
36、什么。2）-Doyouknowourtownatall? -No,thisisthefirsttimeihavebeenhere.注意：句型中it可以用this或that，time可以用成week，year，month等边式时间的名词。如：Thisisthefirstmoththat/yearihavebeenhere.这是我在这儿的地一个月/第一个年头。2、Itis（high/about）timethatsbdid/shoulddosth该句型意为“是该某人做某事的时候了”。这是一个虚拟语气句型，表示与现在事实相反的虚拟语气。如：1)Itstime(that)iwentandpickedupmylittlegirlfromschool.是该我去学校接我女儿的时候了。2）Itshightimetheyrealizedtheproblem. 是他们意识到问题的时候了。3. 用在强调结构中，其结构为： It is /was+被强调部分+that/who-clause