1、The use of“it”(I)He found it difficult to stop smoking I think it best that you should do more exercise.She thought it no good worrying about himIt作形式宾语代替不定式、动词代替不定式、动词-ing短语、或从句。短语、或从句。1.It 用作形式宾语用作形式宾语 当不定式（短语）、动名词（短语）或从句在句子中作宾语时，为当不定式（短语）、动名词（短语）或从句在句子中作宾语时，为保持平衡，避免句式结构的混乱，常用保持平衡，避免句式结构的混乱，常用it i
2、t作形式宾语，而将真正的宾作形式宾语，而将真正的宾语放在句尾。此时语放在句尾。此时it it只起引导作用，无意义只起引导作用，无意义。S+v+it+adj.n(for sb)to do sth.从句从句doing sth+find possible1.S+think +it +necessary +(for sb.)to do sth./clause.feel important Sentence patterns:Sentence patterns:形式宾语形式宾语 a rule2.S+V +it +ones duty +(for sb.)to do sth./clause an honou
3、r 3.S +V+it +no good +doing sth.no use 完成句子（1）They _（发觉难）to finish their work in two days.（2）We _（认为是我们的职责）to clean our classroom every day.（3）It is important _（对她来说）to come to the party.found it difficultthink it our dutyfor her 作形式宾语作形式宾语(Preparatory Subject)为了记忆方便我们把该句型总结为为了记忆方便我们把该句型总结为6123结构结构。
4、6指主句中常用的动词：指主句中常用的动词：think,believe,make,find,consider,feel；1指的是形式宾语指的是形式宾语it；2指的是宾补的两种形式：指的是宾补的两种形式：形容词或名词；形容词或名词；3指的是真正宾语的三种形式：指的是真正宾语的三种形式：不定式短语，动名词短语不定式短语，动名词短语 或从句。或从句。We think it our duty to clean our classroom every day.He felt it important learning English well.They found it difficult that th
5、ey would finish their work in two days.1.The fact that she was foreign made _difficult for her to get a job in that country.(2010.辽宁）A.So B.much C.that D.it 2.The doctor thought _would be good for to have a holiday.（2010.全国II)A.this B.that C.one D.It 3.I dont think _ possible to master a foreign lan
6、guage without much memory work.(MET90)A.this B.that C.its D.it4.It 作形式宾语的特殊用法n1.某些表示“喜、怒、哀、乐”的动词，如like,enjoy,love,hate,dislike,appreciate等等 后后往往不能直接接宾语从句；必须先由必须先由it担任形式宾语担任形式宾语,再接从句再接从句.We would much appreciate it if you could do us that favour.要是你们能帮我们这个忙，我们将非常感激。要是你们能帮我们这个忙，我们将非常感激。Id prefer it if
7、 I didnt have to finish the work.要是我不必完成那项工作，那就太好要是我不必完成那项工作，那就太好了。了。n2.某些含有介词的动词短语如某些含有介词的动词短语如see to,depend on,answer for,rely on,insist on,look to,stick to 等结构中等结构中往往不能直接接宾语从句；必须先由必须先由it担任形式宾语担任形式宾语,再再接从句接从句.Ill see to it that everything is ready in time.我将负责按时做好一切准备。我将负责按时做好一切准备。You may depend o
8、n it that Tom will help you with your English.(你放心，汤姆会帮助你学英语的。你放心，汤姆会帮助你学英语的。)Im counting on it that you will come.我指望着你会来。我指望着你会来。1.I like _ in the autumn when the weather is clear and bright.(MET2004)A.this B.that C.it D.one2.I hate _when people talk with their mouths full.(MET98)A.it B.that C.the
9、se D.themIt is amazing that at my age I am still fit.It is easy to become addicted to smoking.it is no good crying over spilt milk.(覆水难收)It 作形式主语作形式主语代替不定式、动词代替不定式、动词-ing短语、或从句。短语、或从句。2.It 用作形式主语用作形式主语 当不定式（短语）、动名词（短语）或从句在某个句子中作主语时，当不定式（短语）、动名词（短语）或从句在某个句子中作主语时，为保持句子结构前后平衡，避免头重脚轻，因此常用为保持句子结构前后平衡，避免头
10、重脚轻，因此常用it作形式主语作形式主语置于句首，而将真正的主语放在句尾。此时置于句首，而将真正的主语放在句尾。此时it只起先行引导作用，只起先行引导作用，本身无词义。本身无词义。It be+adjnp.p(for/of sb)to do sth主语从句主语从句doing sth+1.It+be+adj.+主语从句主语从句 这是主语从句最常见的一种结构。这是主语从句最常见的一种结构。It is uncertain whether he can come to Jennys birthday party or not.注意：注意：如若形容词为如若形容词为 important/necessary，
11、good/wrong natural.表达一种要求，命令或者责备时，多使用虚表达一种要求，命令或者责备时，多使用虚拟语气（拟语气（should+V).但是如果只是表示陈述一个事但是如果只是表示陈述一个事实而不是强烈的感情，完全可以用一般的陈述语气。实而不是强烈的感情，完全可以用一般的陈述语气。不过考试建议你还是多用虚拟语气不过考试建议你还是多用虚拟语气It is important that we(should)learn English well.It is necessary that he(should)remember these words.2.It+be+过去分词过去分词+主语从句
12、主语从句，这类过去分词有：这类过去分词有：announced,believed,expected,hoped,decided,reported,said,shown等，等，如：如：It is reported that 16 people were killed in the earthquake.It is not decided who will give the operation to the patient.It is said that he has come to Beijing.注意：注意：如果如果主句中的过去分词是表示请求，建议，命令主句中的过去分词是表示请求，建议，命令等词
13、如：等词如：suggested/ordered/demanded/insisted/commanded.等时等时 that后的从句要用虚拟语后的从句要用虚拟语（should+动词原形），动词原形），should 可以省；可以省；常译为，常译为，“据建议；有命令）据建议；有命令）It is suggested that the meeting(should)be put off.It was ordered that we(should)arrive there in two hours.3.It+be+名词词组名词词组+主语从句主语从句这类名词有：这类名词有：a fact,a pity,a s
14、hame,an honour，a question等，如：等，如：Its a pity that you missed the exciting football match.It remains a question whether he will come or not.注意：如若表示出乎意料之意时注意：如若表示出乎意料之意时,从句一般用虚拟语气从句一般用虚拟语气常译为常译为“竟竟然然”。没有这种意义时，则不用虚拟语气。没有这种意义时，则不用虚拟语气。It is a pity that such a thing(should)happen in your class.4.It+不及物动词不
15、及物动词+主语从句主语从句 这类不及物动词有：这类不及物动词有：appear,seem happen，matter等。译为好像等。译为好像/碰巧碰巧/如：如：nIt seemed that he didnt tell the truth.nIt happened that I was out when he called.n5.It+be+形容词形容词+（for sb.）+动词不定式动词不定式 这类句型常用形容词这类句型常用形容词easy,difficult,hard,important,possible，wise等作表语，有时候为了强调不定式动作等作表语，有时候为了强调不定式动作的执行者，常
16、在不定式前加的执行者，常在不定式前加for sb，译为，译为“对某人来说对某人来说做某事怎么样做某事怎么样”如：如：Its necessary for the young to master two foreign language.It is unwise to give the children whatever they want.n6.It+be+形容词形容词+of sb.+动词不定式动词不定式 这类形容词常是表示这类形容词常是表示心理品质心理品质,性格特征的形容词性格特征的形容词，如：如：kind,nice stupid,clever,foolish,polite,impolite,
17、silly,selfish,considerate等。某人和等。某人和这些形容词可以构成主系表结构。如：这些形容词可以构成主系表结构。如：nIts very kind of you to help me with the work.=You are kind to help me.nIt seemed selfish of him not to share his dictionary with others.=He seemed selfish not to share his dictionary with others.v7.It+be+名词词组名词词组+动词不定式，动词不定式，如：如：
18、It is not a good habit to stay up too late.8.It+be+名词或形容词名词或形容词+动名词动名词，这类名词和形容词常常是：这类名词和形容词常常是：good,no good,no use,a waste of,useless,senseless等，如：等，如：Its a waste of time talking to her any more.It is no use arguing about the matter with him.l9.It+take(sb.)+时间（金钱）时间（金钱）+动词不定式，动词不定式，译为，做某事花了某人多长时间或多少
19、钱。如：译为，做某事花了某人多长时间或多少钱。如：It took the workers almost three years to finish building the dam.It will take a whole day to get to the top of the mountain on foot.实战练习实战练习高考真题高考真题1.In fact is a hard job for the police to keep order in an important football match.(2001 上海上海)A.this B.that C.there D.it2.is
20、a fact that English is being accepted as an international language.(NMET1995)A.There B.This C.That D.It 3.Is necessary to take off our shoes when we enter the lab?(MET88)A.everyone B.this C.her D.it4._ will take you a lot of time to find him in the crowd.A.It B.I C.We D.They5.It is no use his _ ther
21、e,the situation is hopeless now.A.to go B.to be going C.going D.having gone 6.Is _ necessary to complete the design before National Day?(MET89)A.this B.that C.it D.he 7.Does _ matter if he cant finish the job on time?(MET91)A.this B.that C.he D.it8、(2006,全国全国)It is no _ arguing with Bill because he
22、will never change his mind.A.use B.help C.time D.way9.(2004,北京北京)The Foreign Minister said,“_ our hope that the two sides will work towards peace.A、This is B、There is C、That is D、It is The Usage of“it”常见用法常见用法特殊用法特殊用法6123三大句型三大句型形式主语形式主语形式宾语形式宾语Summary九个九个句型句型It be+adjIt be+nIt be+p.pHomework 世纪金榜世纪金榜unit3 语法专练语法专练选择选择1-10
