1.  It + be + 時間 + since-clause

這個句型表示從since 從句謂語動作發(fā)生以后到現(xiàn)在或過去所經(jīng)過的一段時間，意為“自從......以來已多久了”，主句多用一般現(xiàn)在時，從句用一般過去時，如果表示過去的情況，主句用一般過去時，從句用過去完成時，或主句用過去完成時，從句用一般過去時。例如：

It is three years since his father passed away . (從現(xiàn)在算起)

It was 10 years since they married . (從過去算起)

It had been fifteen years since she left Shanghai . (從過去算起)

30 years has passed since we joined the Party . (從現(xiàn)在算起)

2.  It + be + 時間 + before-clause

這個句型中的時間一般為表示一段時間的詞語(如：long years , months , weeks , days ,hours , minutes ) ，主句中的謂語動詞用肯定式，意為“過多長時間才......”。主句的謂語動詞是否定式時，意為“沒過多長時間就......”。主句的時態(tài)可用過去時was或?qū)�來時will be；用was 時，before從句的動詞用一般過去時；用will be 時，before從句常用一般現(xiàn)在時。 例如：

It was not long before she learned those poems by heart . 她沒過多久就背會了那些詩歌。

It was long before the police arrived .過了很久警察才來。

It will be hours before he makes a decision . 要過好幾個小時他才會作出決定。

It will not be hours before meet again . 要不了幾個小時我們還會再見面的。

3.  It + be + 時間 + when-clause

這個句型中, it 指時間，而且表示時間的詞語前沒有介詞(時間一般為具體時間)。主句中的謂語動詞和從句中的謂語動詞在時態(tài)上一般是一致的，主句是will be，when從句用一般現(xiàn)在時代替將來時。例如：

It was already 8 o'clock when we got home .

It was the next morning when we finished our work .

It will be midnight when they get there .

4.  It + be + 時間 + that-clause

這個句型是個強調(diào)句型。例如：

It was two years ago that he made an important invention .

(原句是：He made an important invention two years ago . )

It was at 5 o'clock that he practised playing the violin in the morning .

(原句是：He practised playing the violin at 5 o'clock in the morning . )

比較：It was 5 o'clock when he started in the morning .

(5 o'clock前沒有介詞，這是個定語從句)

5.   It + be + time +  that-clause

這個句型屬虛擬語氣結(jié)構(gòu)，不管主句中用的是 is 或 was ，that從句都須用動詞的過去式或should + 動詞原型(但不及用過去式普通)，在time之前有時可加上high或about 以加強語氣。例如：

 It is time(that)we handed in our exercises .(= It is time that we should hand in our exercises .)

It is high time  (that ) she wrote a letter to her boyfriend .

6.  It / This / That + the first(second , third …) time + that-clause

這個句型表示截止到說話時為止的某人的一種經(jīng)歷，關(guān)鍵是注意time前有序數(shù)詞，主句是 is 時 ，從句要用現(xiàn)在完成時；如果主句用一般過去時was ，則從句須相應(yīng)地用過去完成時。例如：

This is the first time (that) these Europeans have visited the Great Wall .

It was the fifth time (that) I had paid a friendly visit to Africa .

二、It代替從句作形式主語的常見句型

1. it 代替連詞 that 引導(dǎo)的從句作形式主語。

1) it + be + 過去分詞 + that 從句

It's said that Tom has come back from abroad . 據(jù)說湯姆已經(jīng)從國外回來了。

It was reported that dozens of  children died in the accident . 據(jù)報導(dǎo)，數(shù)十名兒童在事故中死亡。

可用于該句型的過去分詞還有：known , thought , told , believed , hoped , announced ,expected , decided , suggested等，該句型常可以轉(zhuǎn)換成含有賓語從句的復(fù)合句或者含有不定式作主補的簡單句。如：

 It's said that Tom has come back from abroad . →People say that Tom has come back from abroad . →He is said to have come back from abroad .

2) It + be + 名詞詞組 + that 從句

It's a pity that he can't swim for his age . 真遺憾，就他的年齡來講，他竟不會游泳。

It's a wonder that you could finish such a hard task in such a short time . 真奇怪，你竟能在如此短的時間內(nèi)完成艱巨的任務(wù)。

可用于該句型的名詞詞組還有：an honour , a good thing , a fact , a surprise , good news等。

3) It + be /seem + 形容詞 + that 從句

It is likely that they will beat us tonight .今晚很可能他們會贏我們。

It doesn't seem that she will give us a hand .她幫我們的可能性似乎不太大。

可用于此句型的開容詞還有；wonderful , true , good , right , wrong , (un)important ,useless , surprising , clear , possible , unusual , lucky , certain 等。

4) It + seem / appear / happen + that 從句

It seems that he enjoys pop songs very much .看來他非常喜歡流行歌曲。

It appears that Tom might change his mind .看來湯姆會改變主意。

It happened that I went out that day .碰巧我那天外出了。

注意，句型4可轉(zhuǎn)換成含不定式的簡單句。如上述句子可轉(zhuǎn)換為：

He seems to enjoy pop music very much . / Tom appears to change his mind ./ I happened to go out that day.

2. it 代替連接代詞或連接副詞引導(dǎo)的從句作形式主語。

1) It is  known (not decided , not made clear ,  found out ,  discussed , being discussed , being considered , a question , uncertain等) + 連接代詞或連接副詞引導(dǎo)的從句。

It is still a question when we shall have our sports meet . 我們將什么時候舉行運動會還是一個問題。

It is uncertain whether he can attend this conference or not . 他能否來開會還不能確定。

2) It doesn't matter(doesn't  matter too much , doesn't make too much difference等) + 連接代詞或連接副詞引導(dǎo)的從句。如：

It doesn't matter whether we go together or separately . 我們一起去還是分開去都可以。

It doesn't matter too much to me what you do or where you go . 你做什么或去什么地方，對我都無關(guān)緊要。

【動腦動手】

單元能力立體檢測

1. Tom's mother kept telling him that he should work harder , but           didn't help .

    A. he          B. which           C. she          D. it

〖答案與簡析〗選D。測試 it 用作人稱代詞，代替前文提到過的事物。又如：

1）― The light in the office is still on.

     ― Oh , I forgot            .

     A.  turning it off     B. turn it off     C. to turn it off    D. having turned it off

2）― Have you heard the news about Tom ?

  ― No , what          ?

     A. is it           B. it is          C. are they      D. they are

3）If you don't know the word , why don't you             in the dictionary ?

     A. look at it       B. look after it       C. look up it       D. look it up

答案1）― 3）CAD。值得注意的是，由動詞和副詞組成的短語動詞用it 作賓語時，it 應(yīng)置于動詞和副詞之間。

2. Is               necessary to tell his father everything ?

     A. it         B. that            C. what         D. he

〖答案與簡析〗選A。測試 it 用作形式主語，代替由不定式（或不定式復(fù)合結(jié)構(gòu)）、動名詞或從句表示的真正主語。又如：

1）Is               possible to fly to the moon in a spaceship ?

     A. now            B. man           C. that            D. it

2）Is               necessary to complete the design before National Day ?

     A. this             B. that            C. he              D. it

3）Does           matter if he can't finish the job on time ?

     A. this             B. that            C. he              D. it

4）It worried a bit          her hair was turning grey .

     A. while          B. that            C. if D. for

答案1） ―  4）DDDB。

3. I don't think              possible to master a foreign language without much memory work .

A. this B. that   C. its     D. it

〖答案與簡析〗選D。測試 it 用作形式賓語，代替由不定式、動名詞或從句表示的真正賓語。當(dāng)賓語有自己的補足語時，用it作形式賓語，真正賓語放在補足語之后。常用這種句型的動詞有think , make ,  find , feel , consider 等。

4. Was it in this palace           the last emperor died ?

A. that       B. in which          C. in where            D. which

〖答案與簡析〗選A。測試it 用在強調(diào)結(jié)構(gòu)中，為了強調(diào)句子的某一成分（通常是主語、賓語或狀語），常用強調(diào)It is (was) + 被強調(diào)成分 + that(或who）…。被強調(diào)部分指人時用 that 或 who ，在其它情況下（包括強調(diào)時間或地點狀語）用that 。又如：

1）Was it during the Second World War            he died ? (MET 88）

     A. that             B. which        C. in which            D. then

2) It was not            she took off her dark glasses            I realized  she was a famous film star .

     A. when ; that  B. Until ; that              C. until ; when       D.  when ; then

答案 1) A  2) B。

5. But         was only the manager . (MET 91完型填空)

     A. this             B. that            C. she            D. it

〖答案與簡析〗選D。測試 it 可以用作指示代詞，指人。當(dāng) it 這樣用時，所指的是心目中己知的或上下文中的人或事物，也可用來指嬰兒。

6. ― What was the party like ?

   ― Wonderful . It's years           I enjoyed myself so much .

     A. after           B. before        C. where        D. since

〖答案與簡析〗選D。測試it 用在某固定短語或句型中。如believe it or not (信不信由你）, take it easy (別著急，慢慢來）， it is (has been )…since…(某人干某事經(jīng)過了多長一段時間），It seems that …(好象)，It happens that …(碰巧) ，It looks as if … （好象），It is one's turn to do …(該輪到誰干……) 等。又如：

Take it          . Everything will be fine in a day or two .

     A. easy            B. quiet          C. calm          D. light

答案是A 。

7. It was Shanghai        the Communist Party of China was founded .

     A. where         B. that            C. at which            D. that where

〖答案與簡析〗選A。測試強調(diào)句與定語從句不能混淆，這里是定語從句。若把Shanghai 的前面加上介詞 in 時，就是強調(diào) 地點，這時就可以選 B。

1. Tom's mother kept telling him that he should work harder , but            didn't help .

     A. he        B. which        C. she            D. it

2. I was disappointed with the film , I had expected              to be much better .

     A. that             B. this            C. one            D. it

3.             is a fact that English is being accepted as an international language .

     A. There          B. This           C. That           D. It

4. As                 happens , I have brought my umbrella with me .

     A. it         B. this            C. that            D. such

5.                has already been pointed out , grammar is not a set of dead rules .

     A. As              B. It D. That   D. This

6. It was seven forty-five             he finished the work .

     A. when          B. that            C. when         D. before

7. I have no idea                  is so far the airport from here .

     A. what           B. how           C. it D. that

8. Was it because it snowed last night                 he didn't come ?

     A. why            B. that            C. when         D. which

9. Does            matter if he can't finish the job on time ?

     A. this             B. that            C. he              D. it

10. Is                unnecessary to tell his father everything ?

     A. that           B. it C. he       D. this

11. European football is played in 80 countries , making               the most popular sport in the world .

     A. which         B. this            C. that            D. it

12. We are going to hold a meeting tomorrow afternoon . Please tell Mr Wang about               .

     A. this             B. that            C. it              D. the meeting

13. ― Who is knocking at the door ?

     ―                is me .

     A. It         B. That          C. This           D. where

14. ― What time is it now ?

     ―             is ten o'clock .

     A. The time     B. The o'clock C. It D. That

15. I have seen the baby .            is very active and lovely .

     A. He              B. She            C. Who          D. It

16. He was ill .            is why he didn't come to the meeting .

     A. It         B. This           C. That           D. There

17.            is good news that she has passed the entrance examination for Beijing University .

     A. That            B. This           C. What         D. It

18.            is no doubt that he will succeed in his experiment .

     A. It         B. This           C. That           D. There

19. Look , someone is coming . Who can              be ?

     A. he B. she           C. that man            D. it

20. I find             difficult               him to do such work .

     A. it ; of          B. it ; for        C. that ; of             D. that ; for

21. My pen is lost and I can't find           anywhere , so I must buy            .

     A. it ; one B. one ; it            C. it ; it          D. one ; one

22. We think           useless            theory without practice .

     A. it ; learning B. it ; learn     C. that ; learning           D. that ; to learn

23. It is not you who               in trouble ; it is I who             in trouble .

     A. are ; am      B. are ; is       C. are ; are     D. is ; is

24. She is already 50 , but she doesn't look                .

     A. like             B. this            C. it D. such

25. I don't know what was             for supper .

     A. it         B. there          C. that            D. food

26. Tom's mother kept telling him that he should work harder , but          didn't help .

    A. he          B. which           C. she        D. it

27. ― The light in the office is still on.

     ― Oh , I forgot            .

     A.  turning it off   B. turn it off    C. to turn it off   D. having turned it off

28. ― Have you heard the news about Tom ?

     ― No , what          ?

     A. is it           B. it is          C. are they      D. they are

29. If you don't know the word , why don't you             in the dictionary ?

     A. look at it       B. look after it       C. look up it       D. look it up

30. Is            necessary to tell his father everything ?

     A. it         B. that            C. what         D. he

31. Is            possible to fly to the moon in a spaceship ?

     A. now            B. man           C. that            D. it

32. Is           necessary to complete the design before National Day ?

     A. this             B. that            C. he              D. it

33. Does           matter if he can't finish the job on time ?

     A. this             B. that            C. he              D. it

34. It worried a bit          her hair was turning grey .

     A. while          B. that            C. if D. for

35. I don't think         possible to master a foreign language without much memory work .

     A. this             B. that            C. its              D. it

36. Was it in this palace              the last emperor died ?

     A. that             B. in which            C. in where            D. which

37. Was it during the Second World War               he died ?

     A. that             B. which        C. in which            D. then

38. It was not              she took off her dark glasses            I realized  she was a famous film star .

     A. when ; that  B. Until ; that              C. until ; when       D.  when ; then

39. But            was only the manager . (MET 91完型填空)

     A. this             B. that            C. she            D. it

40. ― What was the party like ?

   ― Wonderful . It's years               I enjoyed myself so much .

     A. after           B. before        C. where        D. since

41. Take it           . Everything will be fine in a day or two .

     A. easy            B. quiet          C. calm          D. light

42. It was Shanghai               the Communist Party of China was founded .

     A. where         B. that            C. at which            D. that where

43. I  find             difficult              him to do such work .

     A. it ; of          B. it ; for        C. that ; of      D. that ; for

44.             take to fly to Paris from Beijing ?

     A. How long does that                  B. How long does it

     C. How soon does it               D. How far does it

45. You made a new model plane ,                .

     A. how wonderful it is                  B. how wonderful is it

     C. that is wonderful                     D. wonderful you are

答案：1 ― 5 DDDAB 6 ― 10 ACBDB  11 ― 15 DCACD  16 ― 20 ADDDB      21 ― 25 AAACB26 ― 30 DCADA  31 ― 35 DDDBD  36 ― 40 AABDD  41 ― 45 AABBA

【創(chuàng)新園地】

When I got into his house , I saw an old man reading

a book in the chair . I talked with him . I found that      1 . ____

from the time when he was a child , he always brought         2 . ____

a little book in his pockets . He did reading almost                3 . ____

every minute . He did not do anything . People often found   4 . ____

him read a book while he was waiting for meals ,                 5 . ____

buses , doctors , plays begin or something to happen .           6 . ____

You could still even find him reading in the toilet .               7 . ____

That was why he found his fifteen minutes a                        8 . ____

day for reading . That was how he reads twenty                    9 . ____

books a year―one thousand in our lifetime .                        10 . ___

（請同學(xué)們改好后把答案反饋給我們）

【創(chuàng)新園地】答案：1. the → a 。 2. brought → carried  。3.  √。 4. 在 anything 后加 else 。5. read → reading 。 6. 在begin 前加 to 。 7. 去掉 still 。8. why → how 。 9. reads → read 。10. our → his 。

【同步題庫】

Unit   14

Ⅰ . 單項填空

答案：Ⅰ. 1 ― 5 BDDAA  6 ―10 CABDA  11 ― 15 CCADB  16 ― 20 DBACD  21 ― 25 BDBAC  Ⅱ. 1 ― 5 DBCBA  6 ― 10 CABCA  11 ― 15 CDDAD  16 ― 20 BAAAD   21 ― 25 CBDAB  Ⅲ. 1―5 DACCD  6 ―10 ACDBC 11 ― 15 CFEGD  Ⅳ . 1 . darkness / dark 2 . journey 3 . forced 4 . simple 5 . forehead 6 . wonder 7 . length 8 . satisfied 9 . smelly 10 . zones  Ⅴ . 1 . expected→expecting 2 . 去掉 reached 后面的 to 3 . usually→usual 4. same→the same 5 . 去掉 in 6 . 去掉 for 7 . √  8 . 在 much 前加 how 9 . spend→spending  10 . anyone→everyone

Ⅵ . One possible version:

Dear Mr Zhang ,

We know that this is the last lesson that you will give us . Soon we'll graduate and say good-bye to our school . At this moment , we don't know how to express ourselves . All we can say is "Thanks" .

Three years ago when we came to this school , we knew nothing about English . However , with your unselfish help , we have greatly improved our English in listening , speaking , reading and writing . We owe all this to you , because in the past three years , you have been working hard , trying your best to help us . We will remember all those lively and interesting lessons you've given us , which we will never forget .

Now let us all say again , "Thank you ,  Mr Zhang" .