《It的用法姚楠课件》由会员分享，可在线阅读，更多相关《It的用法姚楠课件（53页珍藏版）》请在金锄头文库上搜索。
1、Grammar,it的用法,it 在句中的作用有两个，一是作代词，二是作引导词作代词时， 通常指代前面提到过的人或事物， 或表示季节，气候，距离等作引 导词时，一般用来充当形式主语，形式宾语或用于强调结构，现分述如下：,e.g. It is impossible (for so few workers) to do so much work in a single day. It was foolish of her to waste money on such clothes. 2) It + be + adj. / n. + clause. e.g. It is certain that
2、Tom will do well in the exam.,I.作代词 1.用作人称代词，代替前文所提到的事物 My pen is missing. I cant find it anywhere. Jack is ill. Have you heard about it? The frog is not a warm-blooded animal. Its a cold-blooded one. 2.用以代替指示代词this, that -Whats this?-Its a flag. Whose exercise-book is that?- Its hers,e.g. It will t
3、ake them more than ten years to complete the Three Gorges Dam. 5) It + be + said / reported / told等+that-clause. e.g. It is said that he will leave for Beijing tomorrow.,3. It 作人称代词，指代婴儿或身份不明的人。 E.g -Who is knocking at the door? -Its me. -Who is making such a noise? -It must be the children.,4. 表示天气
4、,时间, 距离,金钱，日期，价值，度量，温度，环境情况等 Its time for lunch. When spring comes, it gets warmer and warmer. Its about 2,000 kilometers from here to the zoo. It is March 29th today. It was getting dark. It rains a lot in New Zealand. It is some 3,500 kilometres from Polynesia to New Zealand.,.,. 作引导词 作形式主语或宾语 it作
5、形式主语常用于： It be+adj./ n./ p.p+不定式/ 动名词/ 主语从句 .代替不定式 To see you again is a pleasure. = It is a pleasure to see you again. To drive too fast is dangerous. = It is dangerous to drive too fast. To master English is necessary for us. = It is necessary for us to master English,注:主要结构有 1) It is/ was +adj/ n
6、.(for/ of sb) to do sth 在此结构中, 当形容词是表示不定式逻辑主语的特征或属性 (如: wise, bright, kind, nice等)时, 介词用of; 形容词用来说明不定式短语 (如: important, possible, necessary, strange等) 时, 介词要用for。 e.g. It is impossible for so few workers to do so much work in a single day. It was foolish of her to waste money on such clothes 2)It +
7、take + (sb.) some time / some money + to do sth. e.g. It will take them more than ten years to complete the Three Gorges Dam,.代替动名词作主语 主要结构有Its no use/ good / useless doing sth. Eg. Its no use crying when you have difficulties. Its no use trying to repair the ship. There is no need to wait for her.,
8、cf.,.代替整个句子作主语 主要结构有: 1) It be clear/certain/possible/true+ that It is possible that one of them kept a kind of bank where the workers could keep their money safe. It is probable that the Chinese team will win that football game.,2) It be + important/ necessary/ right/ strange/ natural /curious+ tha
9、t（虚拟语气，should可省) It was obvious that the man was not on the spot at the time the murder took place. It is necessary that a doctor be sent for at once.,3) It be a pity/ shame/ fact/ my duty that eg. It is a fact that English is being accepted as an international language. It is a good thing that New
10、Zealand helps the Maori to keep their own language and culture. 4) It + be +pp/ v.+ing + that 从句 It be said/ reported/ broadcast/ announced/ known/ learned + that e.g. It is not surprising that he failed in the exam. It is said that he will leave for Beijing tomorrow.,5)It be suggested/ recommended/
11、 required/ demanded+ that+(should)+ do Its not yet known where she has gone. It is known that the earth travels around the sun. Its reported that the troops have crossed the border. Its hoped that the problem will be solved soon. It was proved that he was a thief. It is decided that the general meet
12、ing be put off till next Wednesday afternoon.,6) It happens/ appears/ seems/ occurs that碰巧，似乎 It happened that I was driving on the high way when the hurricane hit the area. 7) It looks/ seems as if看上去似乎 It looks as if it is going to snow again. 8) It + vt. + sb. + that-clause. e.g. It worried her a
13、 bit that her hair was turning grey.,It作形式宾语，用来代替不定式、动名词或从句。常用于以下结构： feel/find/consider/think/make+it+adj./n.+真正的宾语 （如：不定式、动名词或从句） E.g I think it no use talking with him about that. We found it hard to get along with him I consider it impossible to finish the job today. Do you feel it no good learni
14、ng without practice? He made it a rule that he would never come late. We felt it strange that no one would take the money.,1. It is time (about time/ high time) that过去时( should+ do ) 是该.的时候了 Eg. It is time the children went to bed. 2. It is the first/ second time (that) +现在完成时 It was the first/ seco
15、nd time (that)+过去完成时 (it 可用this/ that代替） Eg. It/This is the first time I have come to visit the city.,在其他句式中,3. It be +一段时间since（过去时短暂动词）“自从（短暂动词表示的动作开始）干 以来，已经有多久” It be +一段时间since（过去时延续性动词）“自从（延续性动词表示的动作结束）不干以来，已经有多久”,It is five years since I left my hometown.我离开家乡已经五年了 It is five years since I li
16、ved in the quiet little town. It is quite some time since I smoked.我戒烟已经有一段时间了,4. It be +时间点when当的时候是几点钟 It was five oclock in the afternoon when they reached the museum. It be +时间段+ before .才/就 It seemed only seconds before Tom finished his homework. It will be three years before we can meet again.,5. It 用于强调句型 It is/was + 被强调部分 + that + 句子的其余部分, it 本身没有词义 注意: 1). 强调句可以强调主语、宾语、状语 E.g. It is Sally who/that wants to se
