1、 Unit 4 Breaking Boundaries Grammar It as an empty subject Watch and Think What we have learnt about it before1.I bought a new house and it needed to be painted and decorated.(it-a new house)2.Whats that?It is a new device.(it-that)3.Someone must have been here.But we have no idea who itwas.it-a cer
2、tain person4.The new couple got a baby and it was very lovely.(it-a baby)5.He smoked in bed and I dont like it.(it-He smkoed in bed)6.By that time,the panda no longer needed _(it)mother for food.7.The cat can wash _(it)BBy that time,the panda no longer needed _(it)mother for food.y that time,the pan
3、da no longer needed _(it)mother for food.By that time,the panda no longer needed _(it)mother for food.6.The cat can wash _.By that time,the panda no longer needed _(it)mother for food.6.The cat can wash _.Whats thisa new machine.itsitselfit 作为人称代词，可以指前面提到的事物，或特定的人或不知性别的婴儿。也可以指前面提到的片语或整个句子，此时，相当于that
4、。物主代词和反身代词为itself8.It is a lovely day,isnt?9.It was nearly midnight when she came back.10.It is March 8,Womens Day.11.It is some 2,300 kilometers from Beijing to Guangzhou.12.It is 39 degree!You may have got a fever.13.It is 15 dollors.14.It lies at the foot of the mountain.s 39 degree!You got a hig
5、h fever!it 作为无人称代词，可以是时间、地点、距离、天气、气温等自然现象。温馨提示：当我们在表示今天、明天、昨天干什么或是什么，用it作主语，今天、明天、昨天作状语，如：今天是星期五：It is Fraday today.一般不能翻译成：Today is Friday Watch and Think What we will learn about it from the following1.But it is vital not to take any chances.2.when I saw the tragic scenes on the news,I felt it was
6、 my duty as a doctor to go there and offer my help.3.It took them a year to build the bridge.4.It is a waste of time doing such useless things.5.It is suggested that each student sing an English song at the class meeting.6.It doesnt matter whether he comes or not.以上例句中的it 作形式主语，真正主语为不定式（短语）、动名词（短语）或
7、从句。it常代替由不定式短语、动名词短语或从句表示的真正主语，作形式主语，而将真正的主语后置it常代替由不定式短语、动名词短语或从句表示的真正主语，作形式主语，而将真正的主语后置常代替由不定式短语、动名词短语或从句表示的真正主语，作形式主语，而将真正的主语后置。常代替由不定式短语、动名词短语或从句表示的真正主语，作形式主语，而it常代替由不定式短语、动名词短语或从句表示的真正主语，作形式主语，而将真正的主语后置。将真正的主语后置。it常代替由不定式短语、动名词短语或从句表示的真正主语，作形式主语，而将真正的主语后置。it作形式主语，所代替的是句子的逻辑主语，并无实际词义还可以保持句子的结构平衡
8、，避免主语过长，显得头重脚轻。it作为形式主语主要分为三种情况。一、代表不定式，根据句子的谓语又可分为谓语四种类型：1.1）be+形容词+（for/of sb.)+不定式 eg As far as im concerned,it is necssary for us to deal with stress.It is really kind of you to give me a lift home.2.be+名词+不定式 (It is+n.+to do sth.)eg It was her duty to clean the room.It is a shame for us to have
9、 lost the game.3.be+介词短语+不定式 eg It was against my principle to do that.4.及物动词+宾语+不定式 It cost 150 yuan to buy tohbuy the dress.It took me a yeafinish it.e dress.It took me a year to finish it.二、代表动名词，一般以“be+名词”作谓语。Its no use/good/fun/a waste of time doing sth.It is a waste of time doing such useless
10、things.It is no use giving him some constructive advice.做某事没有用/没有好处/没有意思/是浪费时间三、代表从句，具体可分为六种类型：1.It+be+形容词+从句 (It is+adj.+从句)eg It is natural that she should know everything about it.2.It+be+名词+从句 (It is+n.+从句)It is a question how he did it.It is now wonder that he is asleep3.It+动词的被动语态+从句(known,sai
11、d,reported,agreed.)eg It is not decided who will take over the company.4.It+be/其他系动词(seem,look)+that从句 eg It may be/seems that he views the issue from a different perspective.5.It+动词+that.1)It happened that there was a doctor on the spot.2)It hit/occurred to me/struck me that I hadnt finished my hom
12、ework.6 It doesnt matter whether/if Does it matter if/whether.It doesnt matter if you miss the bus,because theres another one 15 minutes later.注意事项：1.It is important/necessary/right/strange/natural/that(should)do It is a necessary that you do enough exercises before the race.2.It be+suggested/ordere
13、d/advised/commended/required.that(should)+doI suggested that we play a game of chess.-Whos that at the door?-_is the milkman.四四、it 的其他常见句型1）该是我们回家的时间了。It is time that we should go/went home.2)我收到你的信两天了。It is three days that I received your letter.3)这是我第一次参观长城。It/This/That is the first time that I ha
14、ve visited the great Wall.4)过两周我们就要考试了。It will be two weeks before we take an exam.5)我三点完成作业。It was three oclcok when I finished my work.6)这是我读过的最好的一本小说了。It/That/This is the best novel that I have ever read.7)He is clever and studies hard.And It is the same with his brother.8)我是在昨天的聚会上认识他的。It was at
15、 the yesterdaays party that i got to know him._7)It is the same with sb./sth.He is clever and studies hard.And _（他哥哥也一样）。1.It is time that.did/should do.2.It is(hasbeen)/was(had been)+段时间名词+since .did/had done3.It/This/That is/was the first/.time that.have done/had done.4.It will(wont)be/was(not)+段时
16、间名词+before .do/did.5.It was+点时间+when.did.6.It/This/That is/was+最高级+that .have done/had done.7.已的情况也适合于甲的情况。It is the same with./It is true of./So it is with.8.强调句：It is/was+被强调部分+who/that+原句剩余部分 做某事没有用/没有好处/没有意思/是浪费时间五、常见there be 句型和it形式主语的辨析：（翻译下面各句）1.找到你家困难。_2.他很诚实，这没有任何怀疑。_3.你没有必要担心他的安康。_4.和他争辩这个
17、问题没有意义。_5.没有办法解决这个问题。_6.There is no denying the fact._7.There is no hurry to do sth._8.没有时间去度假。_1.There is difficulty(in)finding your house.2.There is no doubt that he is honest.3.There is no need for you to worry about his health.4.There is no sense/point(in)arguing about the matter.5.There is no w
18、ay of solving/to solve the problem.6.不否认7.没有必要匆忙做8.There is no time to spend a holiday.单击此处添加标题 巩固练习一、单句语法填空1.From the teachers patient explaintion,I have learnt what a big responsibility _is to educate.2.I know _is important to know my own limitations,but what is difficult is to help others to know
19、 their own limitations.3.It _(know)to us that he is one of the most famous football players in the world.4.It never occurred to me _you could succeed in persuading him to change his mind.5._felt funny watching myself on TV.6.An average of just 18.75 cm of rain fell last year,making _the driest year
20、since California became a state in 1850.7.By that time,the panda no longer needed _(it)mother for food.单击此处添加标题8.To our surprise,the door opened of _(it).9._,in the middle of the bush,was a little bird,singing to the sky.10._is no wonder that such a top student is addicted to online games.11._happen
21、ed that there was a doctor in the crowds.12.You can never imagine how difficulty _ was finding the missing kid in the mountain.13.It is careless _you to make so many mistakes in the exam.14._is no point in getting upset about it.-Lets just try to find a solution.15.-Whos that at the door?-_is the mi
22、lkman.16._is three years since my little brother joined the army.17.It wont be long _ we will selebrated the Spring Festival.18.I wonder where _was that you got to know each other.19.Today we celebrate._is exactly one month since the last reported case.二、用it作主语，改写下面句子。1.We all know that they have br
23、oken their promise.2.To get to my school from my home by bike takes me half an hour.3.Dont you think trying to get Betty to change her mind is a waste of time?4.That all human beings can makee a difference to the society is my belief.5.As is reported,the English summer camp will offer many useful co
24、urses available to everyone.6.You are careless to make so many spelling mistakes in the composition.7.Spending time on your business card to make it creative and memorable is worth.8.I received your email three days ago.Key一、1.It 2.It 3.is known 4.that 5.It 6.it 7.its 8.itself 9.There10.It 11.It 12.
25、there 13.of 14.There 15.It 16.It 17.before18.it 19 it.二、1.It is known to us that they have broken their promise.2.It takes me half an hour to get to my school from my home by bike.3.Dont you think it is a waste of time getting Betty to change her mind?4.It is my belief that all human beings can make
26、e a difference to the society.5.It is reported that the English summer camp will offer many useful courses available to everyone.6.It is careless of you to make so many spelling mistakes in the composition.7.It is is worth spending time on your business card to make it creative and memorable.8.It is three days since I rceived your email.
