it的用法 (2)

1、it 的用法一、考查一、考查 it 用作形式主語的用法用作形式主語的用法當(dāng)不定式、動(dòng)名詞、從句等用作主語時(shí)，為避免頭重腳輕，通常在句首使用形式主語it，而把真正的主語放在句子末尾。如：Its no good sitting up too late. 熬夜沒有好處。It is quite clear that he has read the book. 很顯然，他讀過這本書。It doesnt matter what he says. 他說什么沒關(guān)系?！咎貏e提醒】注意it用作形式主語的三類特殊句式：1.用作動(dòng)詞look, seem, appear, happen, occur, follow等的

2、主語(后接that從句或as if從句)。如：It seems that he knows everything. 他好像什么都知道。It (so) happened that I had no money with me.碰巧我沒帶錢。It occurred to me that he helped me a lot.2.當(dāng)系表結(jié)構(gòu)后接有if 或when引出的狀語從句時(shí)，通常在系表結(jié)構(gòu)前使用形式主語表示說話人對(duì)某情況的看法。如： It was a great surprise to me when he did a thing like that. 他這樣做使我很吃驚。It would be

3、 a tragedy if anything went wrong. 如果出了什么事就是一個(gè)悲劇。3.用于if it were not for / if it hadnt been for(若不是因?yàn)?。But for如：If it hadnt been for the freezing wind they could have reached the injured man in time. 要不是有刺骨的寒風(fēng)，他們就及時(shí)趕到傷員身邊了。二、考查二、考查 it 用作形式賓語的用法用作形式賓語的用法當(dāng)不定式、動(dòng)名詞、從句等用作賓語且其后跟有賓語補(bǔ)足語時(shí)，就應(yīng)在賓語補(bǔ)足語前使用形式賓語，而將真正

4、的賓語移至句末： We found it difficult to persuade her. 我們發(fā)現(xiàn)很難說服她。He makes it a rule to get up before dawn. 他習(xí)慣于天亮前起床。I think it very strange that he goes out walking almost every night. 我認(rèn)為他幾乎每晚都出去散步是很奇怪的?！咎貏e提醒】注意it用作形式賓語的三類特殊句式：1. 動(dòng)詞+it+if / when從句當(dāng)enjoy, like, dislike, love, hate, prefer, appreciate等動(dòng)詞后需

5、要接一個(gè)if或when引導(dǎo)的從句時(shí)，此時(shí)必須要先在動(dòng)詞后接it作形式賓語。如：She wont like it if you arrive late. 她不喜歡你遲到。He hates it when people use his bike. 他討厭別人用他的自行車。Id prefer it if I didnt have to do so much work. 要是我不必做那么多工作，那就太好了。I would appreciate it very much if you would help me with it. 如果你能幫助我做這事，我會(huì)十分感激。2. 動(dòng)詞+介詞+it+that從句動(dòng)

6、詞短語allow for（擔(dān)保）、count on（期待）depend on（依靠）、insist on（堅(jiān)持）、 see to（確保） ,answer for等后接that引導(dǎo)的賓語從句時(shí)，必須冠以形式賓語it。 。You may depend on it that he will turn up in time. 你可以相信他會(huì)及時(shí)趕到的。I cant answer for it that the boy is honest. 我不能保證這個(gè)男孩是誠(chéng)實(shí)的。Ill see to it that all these letters will be sent to the post before

7、 twelve. 我將注意讓所有的信件在12點(diǎn)以前送到郵局。3、動(dòng)詞have（表明，堅(jiān)持說）、take（認(rèn)為，猜想）、hide（隱藏）、publish（公布）、put（表達(dá)，寫出來）等后接由that引導(dǎo)的賓語從句時(shí)，往往在從句的前面加上形式賓語。I take it that you will be leaving Shanghai soon.我認(rèn)為你不久就離開上海。We published it that we had finished the project ahead of time. 我宣布我們已經(jīng)提前完成了這項(xiàng)工程。 三、考查三、考查 it 在強(qiáng)調(diào)句中的用法在強(qiáng)調(diào)句中的用法強(qiáng)調(diào)句的基本

8、結(jié)構(gòu)是：It+be+被強(qiáng)調(diào)部分+that(who)+其他部分。It was yesterday that he got married. 他是昨天結(jié)婚的。It was a computer that he bought last week. 他上個(gè)星期買的是一臺(tái)電腦。【特別提醒】對(duì)于強(qiáng)調(diào)句的復(fù)習(xí)要特別注意兩種情形：1.當(dāng)強(qiáng)調(diào)句有插入語或復(fù)雜修飾語時(shí)：It was lack of money, not of effort, that defeated their plan. 他們的計(jì)劃受挫，原因是缺少錢而不是沒有盡力。It was more in sorrow than in anger tha

9、t he criticized his former colleague. 他批評(píng)以前的同事，并非出于氣憤而是為他惋惜。2.當(dāng)強(qiáng)調(diào)為特殊疑問句時(shí)：Who was it that won the World Cup in 1982? 誰贏得了1982年的世界杯? How long ago is it that you last saw her? 你上一次看見她是多久以前的事？四、考查四、考查 it 與與 one 的區(qū)別的區(qū)別兩者均可代替前面提到的事物，區(qū)別是：it指的是與前面已提到的事物為同一物，此時(shí)的it等于“the (this, that, my.)+名詞”；one 指的是與前面已提到的事物

10、為同一類物，此時(shí)的one等于“a+名詞”。比較：I have a dictionary but Ive lent it to Mary. 我有一本詞典，但把它借給瑪麗了。I havent a dictionary; can you lend me one? 我沒有詞典，你能借我一本嗎?五、考查五、考查 it 在習(xí)語中的用法在習(xí)語中的用法包括it的習(xí)語很多，比如make it就是其中很重要的一例。如：You can make it if you hurry. 如果你趕快還可以及時(shí)趕到。He wants to make it as a writer. 他想作一名作家而一舉成名。You neednt

11、 worry; he will make it. 你不必?fù)?dān)心，他會(huì)辦成的。It all depends=that depends 視情況而定if it is convenient to you 如果你方面的話believe it or not 信不信由你take it easy 別著急，慢慢來，別緊張， as it is 但是實(shí)際上，其實(shí)see (to it ) that 設(shè)法使，務(wù)必做到 if it had not been for 若不是=but forit was not long before 不久就cab it 乘車 brave it out 拼命干到底walk it 步行 do/g

12、o it alone單槍匹馬的干beat it =go away 滾make it =succeed in doing 辦成功 六 Its + adj + for/of somebody to do sth選擇of 還是for，要根據(jù)形容詞來決定， 如果表示人的內(nèi)在品質(zhì)，后面引出的名詞既是前面形容詞的主語，也是動(dòng)詞不定式的邏輯主語，那么用of, 這類形容詞有kind, brave, merciful, fine, cruel, selfish, stupid, clever, wise, unfair等； 如果表示難易程度，可能性，等外在的特征，而且所引出的詞只作后面動(dòng)詞不定式的主語，用for

13、這類形容詞有easy, difficult, hard, impossible, possible, convenient 等等。比如： It is easy for you to make it.It is impossible for him to walk 30 miles within one minute.It is very kind of you to help me.It is wise of you to take his advice.七 .it 引起的容易混淆的時(shí)間句型1、 it is/has been +段時(shí)間+since-clause 這個(gè)句型表示從since謂語動(dòng)作

14、發(fā)生以后到現(xiàn)在或過去所經(jīng)過的一段時(shí)間，意思為：“自從以來已經(jīng)多久了”，要注意：since引導(dǎo)時(shí)間狀語從句時(shí)，從句若使用終止性動(dòng)詞，則表示該時(shí)間是從現(xiàn)在算起的 若使用延續(xù)性動(dòng)詞，則表示時(shí)間是從過去算起的。Its five years since they got married. 他們結(jié)婚已經(jīng)五年了。（從現(xiàn)在算起）Its five years since they were married. 他們離婚已經(jīng)五年了。（從過去算起） since從句中常用一般過去時(shí)，若從句中是持續(xù)性動(dòng)詞的一般過去時(shí)， 則表示該動(dòng)作結(jié)束有多長(zhǎng)時(shí)間了。如： It is three years since he smoked

15、. 他不吸煙已有3年了。 試比較： It is three years since he began to smoke. 他吸煙已有3年了。 注意：在這種結(jié)構(gòu)中， since引導(dǎo)的從句絕對(duì)不能用否定式的謂語動(dòng)詞來表示否定意義， 試比較： 他好久沒學(xué)漢語了。 誤：It is a long time since be didnt study Chinese. 正：Its a long time since he studied Chinese. (studied為持續(xù)性動(dòng)詞， 應(yīng)從其動(dòng)作結(jié)束時(shí)算起) since從句:1.如果謂語動(dòng)詞是延續(xù)性動(dòng)詞或是表示狀態(tài)的動(dòng)詞, 時(shí)間應(yīng)該從動(dòng)作結(jié)束時(shí)算起; 如:

16、Its 2 years since I smoked. 我戒煙已經(jīng)兩年了. (抽煙的這個(gè)動(dòng)作是延續(xù)性的) 2.如果謂語動(dòng)詞是非延續(xù)性動(dòng)詞,時(shí)間要從動(dòng)作開始時(shí)算起 如:Its 2 years since I left school. 我離開學(xué)校已經(jīng)兩年了. (離開的這個(gè)動(dòng)作是短暫的) since后如果接短暫性動(dòng)詞，表示肯定的意思； 如果接延續(xù)性動(dòng)詞, 表示否定的意味。It is two months since he was ill.他病好已經(jīng)兩個(gè)月了。It is two months since he fell ill.他病了已經(jīng)兩個(gè)月了。2、It be +段時(shí)間+before-clause

17、-這個(gè)句型中的時(shí)間是段時(shí)間（long years, months, weeks, days, hours, minutes）,主句中的謂語動(dòng)詞用肯定式，“過多長(zhǎng)時(shí)才”。主句謂語動(dòng)詞是否定式時(shí)，“沒過多長(zhǎng)時(shí)就”。It was not long before she learned those poems by heart.她沒過多久就會(huì)背那些詩了。It was long before the police arrived.過多長(zhǎng)時(shí)才就It will be hours before he makes a decision.It will not be hours before we meet ag

18、ain.3、 It be +點(diǎn)時(shí)間+when-clause這個(gè)句型中，it指時(shí)間，而且表示時(shí)間的詞語前沒有介詞，時(shí)間為具體時(shí)間。主句中的謂語部分和從句中的謂語動(dòng)詞在時(shí)態(tài)上一般是一致的，主句是will be時(shí)，從句中用一般現(xiàn)在時(shí)替換將來時(shí)。如：It was already 8 oclock when we got there.It will be late afternoon when they get there.It be +介詞+時(shí)間+that-clause 此句型為強(qiáng)調(diào)句型4.It/This/That be the first(second/third) time that-clause

19、這個(gè)句型表示說話時(shí)為止某人的一種經(jīng)歷，關(guān)鍵是time前面的序數(shù)詞，主句是is時(shí)， 從句要用現(xiàn)在完成時(shí)，主句是一般過去時(shí)，從句要用過去完成時(shí)。This is the first time (that) these Europeans have visited the Great Wall.It was the fifth time (that) I had paid a friendly visit to America. 下面的句型中用there而不用it。There is something wrong with 有毛病There is no doubt of/that 無疑There is no need for/to do 不需要做There