It引起的几个易混淆的时间句型

It引起的几个易混淆的时间句型 在学习中，同学生们对“It + be + 时间 + 从句”这个结构经常混淆不清，下面逐一进行分析。 1. It + be + 时间 + since-clause 这个句型表示从since 从句谓语动作发生以后到现在或过去所经过的一段时间，意为“自从.以来已多久了”，主句多用一般现在时，从句用一般过去时，如果表示过去的情况，主句用一般过去时，从句用过去完成时，或主句用过去完成时，从句用一般过去时。例如： It is three years since his father passed away . (从现在算起) It was 10 years since they married . (从过去算起) It had been fifteen years since she left Shanghai . (从过去算起) 30 years has passed since we joined the Party . (从现在算起) 2. It + be + 时间 + before-clause 这个句型中的时间一般为表示一段时间的词语(如：long years , months , weeks , days ,hours , minutes ) ，主句中的谓语动词用肯定式，意为“过多长时间才.”。主句的谓语动词是否定式时，意为“没过多长时间就.”。主句的时态可用过去时was或将来时will be；用was 时，before从句的动词用一般过去时；用will be 时，before从句常用一般现在时。 例如： It was not long before she learned those poems by heart . 她没过多久就背会了那些诗歌。 It was long before the police arrived .过了很久警察才来。 It will be hours before he makes a decision . 要过好几个小时他才会作出决定。 It will not be hours before meet again . 要不了几个小时我们还会再见面的。 3. It + be + 时间 + when-clause 这个句型中, it 指时间，而且表示时间的词语前没有介词(时间一般为具体时间)。主句中的谓语动词和从句中的谓语动词在时态上一般是一致的，主句是will be，when从句用一般现在时代替将来时。例如： It was already 8 oclock 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 + 时间 + that-clause 这个句型是个强调句型。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 oclock that he practised playing the violin in the morning . (原句是：He practised playing the violin at 5 oclock in the morning . ) 比较：It was 5 oclock when he started in the morning . (5 oclock前没有介词，这是个定语从句) 5. It + be + time + that-clause 这个句型属虚拟语气结构，不管主句中用的是 is 或 was ，that从句都须用动词的过去式或should + 动词原型(但不及用过去式普通)，在time之前有时可加上high或about 以加强语气。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 这个句型表示截止到说话时为止的某人的一种经历，关键是注意time前有序数词，主句是 is 时 ，从句要用现在完成时；如果主句用一般过去时was ，则从句须相应地用过去完成时。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代替从句作形式主语的常见句型 1. it 代替连词 that 引导的从句作形式主语。 1) it + be + 过去分词 + that 从句 Its said that Tom has come back from abroad . 据说汤姆已经从国外回来了。 It was reported that dozens of children died in the accident . 据报导，数十名儿童在事故中死亡。 可用于该句型的过去分词还有：known , thought , told , believed , hoped , announced ,expected , decided , suggested等，该句型常可以转换成含有宾语从句的复合句或者含有不定式作主补的简单句。如： Its 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 + 名词词组 + that 从句 Its a pity that he cant swim for his age . 真遗憾，就他的年龄来讲，他竟不会游泳。 Its a wonder that you could finish such a hard task in such a short time . 真奇怪，你竟能在如此短的时间内完成艰巨的任务。 可用于该句型的名词词组还有：an honour , a good thing , a fact , a surprise , good news等。 3) It + be /seem + 形容词 + that 从句 It is likely that they will beat us tonight .今晚很可能他们会赢我们。 It doesnt seem that she will give us a hand .她帮我们的可能性似乎不太大。 可用于此句型的开容词还有；wonderful , true , good , right , wrong , (un)important ,useless , surprising , clear , possible , unusual , lucky , certain 等。 4) It + seem / appear / happen + that 从句 It seems that he enjoys pop songs very much .看来他非常喜欢流行歌曲。 It appears that Tom might change his mind .看来汤姆会改变主意。 It happened that I went out that day .碰巧我那天外出了。 注意，句型4可转换成含不定式的简单句。如上述句子可转换为： He seems to enjoy pop music very much . / Tom appears to change his mind ./ I happened to go out that day. 2. it 代替连接代词或连接副词引导的从句作形式主语。 1) It is known (not decided , not made clear , found out , discussed , being discussed , being considered , a question , uncertain等) + 连接代词或连接副词引导的从句。 It is still a question when we shall have our sports meet . 我们将什么时候举行运动会还是一个问题。 It is uncertain whether he can attend this conference or not . 他能否来开会还不能确定。 2) It doesnt matter(doesnt matter too much , doesnt make too much difference等) + 连接代词或连接副词引导的从句。如： It doesnt matter whether we go together or separately . 我们一起去还是分开去都可以。 It doesnt matter too much to me what you do or where you go . 你做什么或去什么地方，对我都无关紧要。 【动脑动手】 单元能力立体检测 一、It 与高考题 1. Toms mother kept telling him that he should work harder , but didnt help . A. he B. which C. she D. it 答案与简析选D。测试 it 用作人称代词，代替前文提到过的事物。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 dont know the word , why dont 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，由动词和副词组成的短语动词用it 作宾语时，it 应置于动词和副词之间。 2. Is necessary to tell his father everything ? A. it B. that C. what D. he 答案与简析选A。测试 it 用作形式主语，代替由不定式（或不定式复合结构）、动名词或从句表示的真正主语。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 cant 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 dont think possible to master a foreign language without much memory work . A. this B. that C. its D. it 答案与简析选D。测试 it 用作形式宾语，代替由不定式、动名词或从句表示的真正宾语。当宾语有自己的补足语时，用it作形式宾语，真正宾语放在补足语之后。常用这种句型的动词有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 答案与简析选A。测试it 用在强调结构中，为了强调句子的某一成分（通常是主语、宾语或状语），常用强调It is (was) + 被强调成分 + that(或who）。被强调部分指人时用 that 或 who ，在其它情况下（包括强调时间或地点状语）用that 。又如： 1）Was it during the Second World War he died ? 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 . A. this B. that C. she D. it 答案与简析选D。测试 it 可以用作指示代词，指人。当 it 这样用时，所指的是心目中己知的或上下文中的人或事物，也可用来指婴儿。 6. What was the party like ? Wonderful . Its years I enjoyed myself so much . A. after B. before C. where D. since 答案与简析选D。测试it 用在某固定短语或句型中。如believe it or not (信不信由你）, take it easy (别着急，慢慢来）， it is (has been )since(某人干某事经过了多长一段时间），It seems that (好象)，It happens that (碰巧) ，It looks as if （好象），It is ones turn to do (该轮到谁干) 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 答案与简析选A。测试强调句与定语从句不能混淆，这里是定语从句。若把Shanghai 的前面加上介词 in 时，就是强调 地点，这时就可以选 B。 二、It 精练 40 题 1. Toms mother kept telling him that he should work harder , but didnt 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 didnt come ? A. why B. that C. when D. which 9. Does matter if he cant 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 oclock . A. The time B. The oclock 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 didnt 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 cant 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 doesnt look . A. like B. this C. it D. such 25. I dont know what was for supper . A. it B. there C. that D. food 26. Toms mother kept telling him that he should work harder , but didnt 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 dont know the word , why dont 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 cant 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 dont 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 . A. this B. that C. she D. it 40. What was the party like ? Wonderful . Its 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