it做形式主語的19個(gè)句型

1、It 作形式主語常見句型is/was + 被強(qiáng)調(diào)部分 + that/who . 該句型是強(qiáng)調(diào)句型。被強(qiáng)調(diào)部分可以是主語，賓語，表語或狀語。強(qiáng)調(diào)的主語如果 是人， that 可以由 who 換用。如果把這種句型結(jié)構(gòu)劃掉后，應(yīng)該是一個(gè)完整無缺 的句子。這也是判斷強(qiáng)調(diào)句型與其它從句的方法。2. It is not until + 被強(qiáng)調(diào)部分 + that .該句型也是強(qiáng)調(diào)句型。主要用于強(qiáng)凋時(shí)間狀語，譯成漢語直到才”可以說是not .until . 的強(qiáng)調(diào)形式。It was not until she took off her dark glasses that I realized she was

2、a famous film star.= Not until she took off her dark glasses did I realize she was a famous film star.= I didn't realize she was a famous film star until she took off her dark glasses.3. It is clear /obvious/true/possible/certain that 該句型中 it 是形式主語，真正的主語是 that 引導(dǎo)的主語從句，常譯為 “清楚(顯然，真 的，肯定)”是主語從句最常見

3、的一種結(jié)構(gòu)。It is very clear that he's round and tall like a tree.= That he's round and tall like a tree is very clear.4. It is important /necessary/ right/strange/natural. that .+(should) do該句型和上一個(gè)同屬一個(gè)句型。由于主句中的形容詞不同，that 后的從句中要用虛擬語氣(should +動(dòng)詞原形)，should可以省去。5. It is said (reported, learned) that

4、該句型中的it仍是形式主語，真正主語是that引導(dǎo)的主語從句。 該結(jié)構(gòu)常譯為“據(jù)說(據(jù) 報(bào)道，據(jù)悉)”。6. It is suggested ( ordered, required . ) that . +(should) do該句型和上一個(gè)同屬一個(gè)句型。 主句中的過去分詞是表示請求， 建議，命令等詞時(shí)， that 后的從句要用虛擬語氣(should +動(dòng)詞原形)，should可以省。常譯為“據(jù)建議；有命令)”。7. It is a pity ( a shame . ) that .該句型中， that 后的從句一般用虛擬語氣( should + 動(dòng)詞原形)， should 可省去表示出乎 意

5、料，常譯為“竟然”。沒有這種意義時(shí)，則不用虛擬語氣。It is a pity that such a thing ( should ) happen in your class. 這種事竟然發(fā)生在你們班上，真是遺憾！It is a pity that he is ill. 他生病了，真遺憾！8. It is time ( about time , high time ) that .該句型中that后的從句應(yīng)該用虛擬語氣，值得注意的是常用過去時(shí)態(tài)表示虛擬.有時(shí)也用should +動(dòng)詞原形，should不能省。常譯為是(正是)的時(shí)侯 ”9. It is the first ( second )

6、time that 該句型要和上一個(gè)句型區(qū)別開來。該句型中的 that 從句不用虛擬語氣，而用完成時(shí)態(tài)。至 于用什么完成時(shí)態(tài)，由主句的謂語動(dòng)詞的時(shí)態(tài)決定。如果是一般現(xiàn)在時(shí)，后面從句用現(xiàn)在完 成時(shí)態(tài)；如果是一般過去時(shí)，后面從句則用過去完成時(shí)態(tài)。該結(jié)構(gòu)中that 可以省去； it 有時(shí)用this替換，常譯為 是第一(二)次”It is the first time I have been here.= This is the first time I have been here.10. It is since .該句型主要用作處理瞬間動(dòng)詞的完成時(shí)，又要和表示一段時(shí)間的時(shí)間狀語連用的問題。主 句中

7、是時(shí)間作表語，其時(shí)態(tài)是現(xiàn)在時(shí)或完成時(shí)， since 引導(dǎo)的從句通常是一般過去時(shí)態(tài)，而且 是瞬間動(dòng)詞。如果主句是一般過去時(shí)，從句則用過去完成時(shí)。11. It is . when .該句型中的 when 引導(dǎo)的是一個(gè)時(shí)間狀語從句，主句中的 it 指時(shí)間，表語由具體的時(shí)間 充當(dāng)。常譯為當(dāng)?shù)臅r(shí)候，是 ”12. It be . before .該句型主句中的 it 指時(shí)間 , 主句中的時(shí)態(tài)常是將來一般時(shí)或過去時(shí)兩種時(shí)態(tài)主句中的 表語多是 long, not long , 3 days , 2 weeks 等表示時(shí)間段的詞或短語。常譯為 “之后”13. It happens (seems, looks,

8、appears ) that.該句型中 it 是形式主語， that 引導(dǎo)的是主語從句，主句中的 happen, seem 等詞是不及物動(dòng) 詞It happe ned ( so happe ned ) that he met his teacher in the street. 碰巧It seems that he will be back in a few days. 看來14. It takes sb. to do sth.該句型中的不定式是真正的主語， it 是形式主語，句型中的直接賓語是時(shí)間。 常譯為“做 要花費(fèi)某人”。15. It is no good (use ) doing st

9、h.該句型中的真正主語是動(dòng)名詞短語，主句中的表語可以是 no good , ( not any good ) , no use , ( not any use )。16. It doesn't matter whether ( if ) .該句型中whether (if)引導(dǎo)的從句是真正主語，該句型常譯為 不論(是否)沒關(guān)系。17. It is kind ( of sb. ) to do sth.該句型中的不定式短語是真正主語，如果不定式的邏輯主語是由of 引起，主句中的形容詞必須是能表示邏輯主語特征的形容詞。常見的有 : bad, brave, careless, clever, c

10、ruel, foolish, good ( 好心的 ), honest, horrible, kind, lazy, modest, naughty, nice ( 有教養(yǎng)的 ), polite, rude, silly, stupid, wise, wrong ( 錯(cuò)誤的 )等。這個(gè)句型可以改寫為： sb. is kind to do sth.It is kind of you to say so. = You are kind to say so.18. It is necessary ( for sb. ) to do sth.該句型與上一個(gè)同屬一個(gè)句型。如果不定式的邏輯主語是由for

11、引起，主句中的形容詞通常是表示重要性，緊迫性，頻繁程度，難易，安全等情況的形容詞。常見的形容詞有： important, necessary, natural easy, safe, common, normal, hard, difficult, dangerous, unusual, rare, impossible, pleasant 等。在中的形容詞作表語可以用從句改寫，如：It is important for her to come to the party.= It is important that she (should ) come to the party19. It l

12、ooks ( seems ) as if .該句型中 it 無意義。 as if 引導(dǎo)一個(gè)狀語從句。常譯為， “看起來好象 如果與事實(shí) 不相符合，則用虛擬語氣It作形式主語常見句型(二)動(dòng)詞不定式，動(dòng)名詞或主語從句作主語時(shí)，通常把它們放在謂語動(dòng)詞前，而用it作形式主語，放到句首，常見句型有：1. It + be +形容詞+主語從句，如：It is uncertain whether he can come to Jenny' s birthday party or not.2. It + be + 名詞詞組 + 主語從句，這類名詞有：a fact, a pity, a shame, a

13、n honour，aquestion 等，如：It ' s a pity that you missed the exciting football match.It rema ins a questi on whether he will come or not.3. It + be +過去分詞 +主語從句，這類過去分詞有：announced, believed, expected,hoped, decided, reported, said, show n 等， 女口：It is reported that 16 people were killed in the earthqua

14、ke.It is not decided who will give the operation to the patient.4. It +不及物動(dòng)詞(seem, appear, happen等)+主語從句，這類不及物動(dòng)詞有：appear,happen, seem 等， 女口：It seemed that he didn' t tell the truth.It happe ned that I was out whe n he called.5. It + be +形容詞 + for sb.) +動(dòng)詞不定式這類句型常用形容詞easy, difficult, hard, import

15、ant, possible ，wise等作表語，有時(shí)候?yàn)榱藦?qiáng)調(diào)不定式動(dòng)作的執(zhí)行者，常在不定式前加for sb，如：It ' s necessary for the young to master two foreign Ianguage.It is un wise to give the childre n whatever they want.這類形容詞有：easy, difficult, hard, important, possible ，wise6. It + be +形容詞+ of sb. +動(dòng)詞不定式，這類形容詞常是表示心理品質(zhì)，性格特征的形容詞，如： kind, nice

16、 stupid, clever, foolish, polite, impolite, silly, selfish, con siderate等。某人禾口這些形容詞可以構(gòu)成主系表結(jié)構(gòu)。如：It ' s very kind ofiyto help me with the work.=You are kind to help me.It seemed selfish of him not to share his dict ionary with others.=He seemed selfish not to share his dict ionary with others.7. I

17、t + be +名詞詞組 +動(dòng)詞不定式，如：It is not a good habit to stay up too late.8. It + be +名詞或形容詞+動(dòng)名詞，這類名詞和形容詞常常是：good, no good, no use, awaste of, useless, senseless 等，如：It ' s a waste of time talking to her any more.It is no use arguing about the matter with him.9. It + take ( sb. )+時(shí)間(金錢)+動(dòng)詞不定式，如：It took t

18、he 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.實(shí)戰(zhàn)演練：1. It is gen erally con sidered un wise to give a child he or she wan ts. (NMET 1997)A. howeverB. whateverC. whicheverD. whe never2. In fact is a hard job for the police t

19、o keep order in an important football match.(2001上海)A. thisB. thatC. thereD. it3. is a fact that En glish is being accepted as an intern ati on al la nguage. (NMET1995)A. ThereB. ThisC. ThatD. It4. Is necessary to take off our shoes when we enter the lab (MET88)A. everyo neB. thisC. herD. it5. will take you a lot of time to find him in the crowd.A. ItB. IC. WeD. They6. It is no use histhere, the situati on is hopeless now.A. to go B. to be going C. going D. havi ng gone7. It is n ever too late to lear n,A. is itB. isn ' t it C. does it D. doesn