it句型大掃描
研究近年的高考試卷中可以發(fā)現(xiàn)含it的句型年年考到。可見it句型的重要性和使用的普遍性?，F(xiàn)根據(jù)其用法特點可歸納為２０個句型．
1. It is +被強調部分+ that ...
該句型是強調句型。將被強調的部分放在前面，其它部分置于that之后。被強調部分可以是主語，賓語，表語或狀語。強調的主語如果是人，that可以由who換用。如果把這種句型結構劃掉后，應該是一個完整無缺的句子。這也是判斷強調句型與其它從句的方法。
It was about 600 years ago that the first clock with a face and an hour hand was made.
It was they that (who ) cleaned the classroom yesterday.
It was in the street that I met her father.
2. It is not until +被強調部分+ that ...
該句型也是強調句型。主要用于強凋時間狀語，譯成漢語＂直到．．．才．．．＂，可以說是not ... until ...的強調形式。
It was not until she took off her dark glasses that I realized she was 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引導的主語從句，常譯為＂清楚（顯然，真的，肯定．．．）＂ 是主語從句最常見的一種結構。
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 ...
該句型和上一個同屬一個句型。由于主句中的形容詞不同，that后的從句中要用虛擬語氣（should +動詞原形），should可以省去。建議記住該句型中的形容詞。
It is important that we (should) learn English well.
It is necessary that he (should) remember these words.
5. It is said (reported, learned....) that ...
該句型中的it仍是形式主語，真正主語是that引導的主語從句。該結構常譯為＂據(jù)說（據(jù)報道，據(jù)悉．．．）＂。
It is said that he has come to Beijing.
It is reported that another earth satellite has been put into orbit.
6. It is suggested ( ordered ... ) that ...
該句型和上一個同屬一個句型。主句中的過去分詞是表示請求，建議，命令等詞時，that 后的從句要用虛擬語氣（should +動詞原形），should可以省。常譯為＂據(jù)建議；有命令．．．）
It is suggested that the meeting ( should ) be put off.
It was ordered that we ( should ) arrive there in two hours.
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 +動詞原形），should可省去．表示出乎意料，常譯為＂竟然＂。沒有這種意義時，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后的從句應該用虛擬語氣，值得注意的是①常用過去時態(tài)表示虛擬．②有時也用should +動詞原形，should不能省。常譯為＂是（正是）．．．的時侯．．．＂。
It is time that children should go to bed.
= It is time that children went to bed.
9. It is the first ( second ... ) time that ...
該句型要和上一個句型區(qū)別開來。該句型中的that從句不用虛擬語氣，而用完成時態(tài)。至于用什么完成時態(tài)，由主句的謂語動詞的時態(tài)決定。如果是一般現(xiàn)在時，后面從句用現(xiàn)在完成時態(tài)；如果是一般過去時，后面從句則用過去完成時態(tài)。該結構中that可以省去；it有時用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詞的完成時，又要和表示一段時間的時間狀語連用的問題。主句中是時間作表語，其時態(tài)是現(xiàn)在時或完成時，since引導的從句通常是一般過去時態(tài)，而且是瞬間動詞。如果主句是一般過去時，從句則用過去完成時。
It is ( has been ) 5 years since his father died.
11. It is ... when ...
該句型中的when引導的是一個時間狀語從句，主句中的it指時間，表語由具體的時間充當。常譯為＂當．．．的時候，是．．．＂。
It was 5 o’clock when he came here.
12. It be ... before ...
該句型主句中的it指時間,主句中的時態(tài)常是將來一般時或過去時兩種時態(tài)．主句中的表語多是long, not long , 3 days , 2 weeks等表示時間段的詞或短語。常譯為＂．．．之后．．．＂。
It was 3 days before he went to Beijing.
It will be not long before he finishes his job.
13. It happens (seems, looks, appears ) that...
該句型中it是形式主語，that引導的是主語從句，主句中的happen , seem等詞是不及物動詞．
It happened ( so happened ) 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間。常譯為＂做．．．要花費某人．．．＂。
It took thousands of people many years to build the Great Wall.
15. It is no good (use ) doing sth.
該句型中的真正主語是動名詞短語，主句中的表語可以是no good , ( not any good ) , no use , ( not any use )。
It is no good learning English without speaking English.
16. It doesn’t matter whether ( if ) ...
該句型中whether(if)引導的從句是真正主語，該句型常譯為?。⒉徽摚ㄊ欠瘢疀]關系．．．。
It doesn’t matter if they are old.
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 , cruel , foolish , good（好心的）, honest , horrible , kind , lazy , modest , naughty , nice（有教養(yǎng)的）, polite, rude , silly , stupid , wise , wrong（錯誤的）等。這個句型可以改寫為：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.
該句型與上一個同屬一個句型。如果不定式的邏輯主語是由for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：①important, necessary, natural②easy , safe , common , normal , hard , difficult , dangerous , unusual, rare , impossible , pleasant等?！ ≡冖僦械男稳菰~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 party
19. It looks ( seems ) as if ...
該句型中it無意義。as if引導一個狀語從句。常譯為，＂看起來好象．．．＂如果與事實不相符合，則用虛擬語氣．
It looks as if he is ill.（真的病了）
It looks as if he were ill.（沒有生?。?div style="height:15px;">
It seemed as if he were dying.
20. We think it important to learn a foreign language.
該句型中的it作形式賓語。為了記憶方便我們可稱該句型為"6123結構"。 6指主句中常用的動詞：think, believe, make, find, consider, feel； 1指的是形式賓語it； 2指的是賓補的兩種形式：形容詞或名詞； 3指的是真正賓語的三種形式：不定式短語，動名詞短語或that引導的賓語從句。
We think it our duty to clean our classroom every day.
He felt it important learning English well.
