It-be-时间-从句.docx

It+be+时间+从句 归纳
1. It is/has been+时间段+since+一般过去时
自从...以来已有...久了
例1：It is/has been 10 years since he came here.
这类句型可转化为：
=Ten years has passed since he came here.
这一句型可扩展为：
It was+时间段+since(从句用过去完成时)
例2：It was years since he had arrived in China.
(过去时+since+过去完成时)
He said it was two years since he had joined the army.他说他当兵已有两年了。
需要注意的是since从句的谓语动词一般是非延续性动词，但有时也可用延续性动词或表示状态的词，此时需要注意句子的翻译（瞬顺延反）：
例3：It is three years since she came to our class.
她来我们班已经有三年了。
It is three years since she was in our class.
她离开我们班已经有三年了。
It is half a year since he was ill. 他病愈有半年了。
It is half a year since he smoked.他戒烟有半年了。

2. It+was+时间点+when (从句用一般过去时) 某事发生在什么时间
It will be+时间点+when (从句用一般现在时表将来)
it指时间，点时间前没有介词，when引导的从句是时间状语从句。
例1：It was already 8 o’clock when he came back.
当他回家时已经8点了。
例2：It will be midday when they get home.
当他们到家时将是中午。

3. It+will(not) be +时间段+before+现在时
It wasnot)+时间段+before+过去时
肯定形式表示"过......时间才......”，
否定形式表示"没有过......就......"
例1：It will be another year before he comes here.
例2：It was not long before he came home.
不久他就回来了
It was some time ___ we realized the truth.
A.when　B.until　C.since　D.before

正确答案：D。过了一段时间后我们才了解了真相。

4. It/This is+the+序数词+时间+定语从句(从句用现在完成时) "
这是第一/二/三……次做某事了"，其中that 可省略，
例1：It is the first time (that) I have been here.
(定语从句)该句型可扩展为：
It was+序数词+时间+定语从句(从句用过去完成时)
例2：It was the second time he had been out with her alone.
例3：It’s the second time you____late this week.
A.arrive　B.arrived　C.have arrived　
D.had arrived

正确答案：C。这是这个星期你第二次迟到了。

5. It is+(high) time+that+did(虚拟语气)
从句也可用should+V(原形)
"该做……的时候了",引导词that常省去， 从句谓语动词常用过去时态，或should+V.但其含义并非指过去，而是指现在或将来.
例1：It is (high) time (that) we stopped pollution.
例2：It is (high) time (that) you came/should come　here.
写作中表示建议时也常可用这类句型。
例3：It’s high time we took measures to solve this　problem.

6. It be+时间(被强调部分)+that
在某一时间发生了某事
例1：It was at 6 o’clock that we heard the noise.
例2：It was 3 years ago that he joined the army.
最简单的判断方法是：当表示时间的词前有介词或者后有副词时，一定是强调结构，必用that。
试比较下面句式与强调句的不同之处：
It was already ten o’clock when he arrived.
It is ten years since I met you last.
It was quite some time before he found the elephant.　
以上几句中时间前无介词后没副词故不是强调句型。
类似的题目
1. It was about 600 years ago _____the first clock with a face and an hour hand was made.
A. when B. before C. that D. since

正确答案：C。
2. ---Did Jack come back early last night ?
---Yes .It was not yet eight o’clock _______ he arrived home .
A. before B. when C. that D. until

正确答案：B　他回家时还不到8点。

3. He was told that it would be at least three more months ______ he could recover and return to work.
A. when B. before C. since D. that

正确答案：B。
“多长时间以后某事才发生”。
4 .---What was the party like ?
---Wonderful. It is years ___I enjoyed myself so much.
A. after B. before C. when D. since

正确答案：D。我很久都没玩得这么开心了。

before long 与long before记忆诀窍和用法介绍
记忆诀窍: long 在前"很久前" long在后"不久后"
用法：long before单独使用，一般用在过去完成时的句子里。它后面可以跟从句构成句型：
It was/will be not) long before ....
before 前一般是long, not long 等词。
值得注意的是：主句中的时态只能是一般过去时或一般将来时。
It wasn't long before I found a job.
我没花多少时间就找到了工作。
It won't be long before our contry becomes a developed country.
我们国家很快就会成为一个发达国家。
It was long before he came back.
过了好久他才回来。
It won’t be long before we see each other.
不久我们又会见面的。
before long "很快、不久"=soon常用于将来时态。
I hope to see you before long.
我盼望不久就能见到你。
We've seen that film long before.
我们早已看过那部电影了。
I had waited there long before he arrived.
他来之前，我在那已等了很久。

单独的before作状语，可指现在以前，可用现在完成时态，请牢记，如：
I have never been there before.

1.It　was　not　until　1936________basketball　became　a　regular　part　of　the　Olympic　Games.
A. that　 　B. when 　　C. which　 　D. then
2.It　will　not　be ________we　meet　again.
A. long　before B. before　long　 C. soon　after 　D. shortly　after
3.──He　was　nearly　drowned　once.(02’春招)
──When　was_____
──________was　in　1998　when　he　was　in　middle　school.
A. that; It　 　B. this; This 　　C. this; It　 　D. that; This
4.It　was　evening ________we　reached　the　little　town　of　Winchester.(04天津)
A. that　 　B. until　 　C. since　 　D. before
5.Scientists　say　it　may　be　five　or　six　years ________it　is　possible　to　test　this　medicine　on　human　patients.(04福建)
A. since　　 B. after　　 C. before　 　D. when
6.It　was ______I　met　Mr. Smith　in　London.
A. many　years　that　 　B. for　many　years　since
　　C. since　many　years　ago　when　 　D. many　years　ago　that
7.-What　was　the　party　like？
-Wonderful. It‘s　years _____I　enjoyed　myself　so　much.
A. after　 　B. before　 　C. when　 　D. since
8.It　was　about　600　years　ago ___the　first　clock　with　a　face　and　an　hour　hand　was　made.
A. that　 　B. until　 　C. before　 　D. when
(Keys：AAADCDDA)
关于it的几个重要考点，在此总结一下
1. It was two years ________he realized the truth.
2. It will be two years ________ the economic situation improves.
3. It was two years later ________ he realized the truth.
4. It is /has been two years ________ he lived here.
5. It was midnight ________ he arrived home.
6. It was at midnight ________ he arrived home.
7. It was not until midnight _______ he arrived home.
A. before B. when C. since D. that
「答案与解析」
1、2两个小题都选A. 第一题意为：两年后他才得知真相。第二题意为：经济形式要等两年后才会有所好转。
「归纳」It was/ will be +一段时间+before+句子是高考一个重要考点。意为：多久之后才……
要注意：It will be +一段时间+before+句子，before引导的是一个时间状语从句，所以后面的从句要用一般现在时态表将来。
3. D 此题为强调句型。把It was…that去掉后，句子仍然成立：He realized the truth two years later.
4. C 本句意为：他不住在这儿已经两年了。
「归纳」为since意为自从某时或某事发生以来，故since后从句时，从句的时态应用一般过去时态，而主句应用现在完成时态。如表示某某事发生多久了，则用：It is/ has been+一段时间+since+从句。
「注意」It is/ has been+一段时间+since+从句。在本结构中，从句的谓语动词如为延续性动词时，翻译时要从动作结束时算起。
5. B本句为定语从句，先行词为midnight，在从句中作状语。要注意与第6小题的区别，第6题为强调句型，故答案应为that.
6.D 再看下面两题：
（1） It was the park ________ he first met his wife.
（2） It was in this park ________ he first met his wife.第一题答案应为where，为定语从句；第二题答案为that,为强调句型。
7.D本题亦为强调句型结构：It was not until…that…意为：直到……才……