it was+ 一段时间+since还是before从句

高考It +be+ 时间+ 从句”结构总结一在“It +be+ 时间+ 从句”结构中，引导从句的从属连词有before, that, since, until （till ）, when 等。

这一结构是近几年高考常考的知识点，现将它们的用法小结如下：一、It +be （not ）+ 时间段+before 从句。

其中的主句是肯定式时，意为“过多长时间才……”；主句是否定式时，意为“没过多久就……”。

例如：1. It was not long before the whole country rose and drove the Austrian soldiers from their homeland. 不久，全国人民便奋起反抗，把奥地利军队从他们的国土上赶了出去。

2. It may be five or six years before the new medicine is tested on human beings.要过五六年时间这种新药才能在人身上做试验。

3. It was two months before he designed the bridge. 过了两个月，他设计出了这座桥梁。

二、It +will be （was ）+ 时间段+until 从句若主句中用一般将来时，则从句中用一般现在时，意思是从现在起到从句中谓语动词表示的动作发生时还有多长时间；若主句中用一般过去时，则从句中也用一般过去时，意思是从过去某一时间起到从句中谓语动词表示的动作发生还有多长时间。

例如：1. It will be ten days until my birthday comes. 到我生日还有十天。

2. It was only five minutes until her husband came back from work.当时离她丈夫下班只有五分钟了。

注意：结构“一”与结构“二”在肯定句中几乎可以通用。

It is +一段时间+since…的句型与It has been +一段时间+since…意思相同，since从句用现在完成时。

前者是规范说法，后者是口语说法。

It was+一段时间since从句就用过去完成时。

一、若since引导的状语从句的谓语动词是终止性的过去时He has studied very hard since he came to our school.自从他来到我们学校，他学习就非常努力。

We have been missing them since they left here自从他们离开这里，我们就一直很想念他们。

It has rained a great deal since you left.你走之后下了好多雨。

We have resided in Shanghai since we parted.自从分手以后，我们一直住在上海。

这是最常见的一种用法，此处不再多述。

二、若since引导的状语从句的谓语动词是延续性动词或表示状态的动词的过去式时I haven’t heard any noise since I slept.这句应译为“我醒后还未听到任何声音”。

John is now with his parents in New Y ork, it is already three years since he was a teacher约翰现在和父母一起住在纽约，他不当教师已经三年了。

It's two years since I smoked我戒烟已经两年了。

How long is it since you lived in Shanghai?你离开（没住在）上海多久了？It is half a month since he was a League member.他退团（不当团员）半个月了。

It’s been quite some time since I was last in London我离开伦敦已很长时间了。

时间状语从句before 和since的用法before 和since的用法1.连词before表示“还未...就...；不到...就...；...才...；趁...还没...”Before they reached the station, the train had gone.他们(还没)到达火车站前，火车已经开走了。

We hadn’t run a mile before he felt tired.我们跑了还不到一英里他就累了。

Please write it down before you forget it.趁你现在没忘把它记下来。

2.before的句型：It will be +时间段+before从句，表示“多久之后才”。

It won't be long +before从句，表示“不久之后将...”It will be half a year before I come back.半年后我才回来。

(一般现在时表将来)It won’t be long before we meet again.不久后我们将再见面。

3.since的句型：It is/has been+时间段+since从句。

若从句的谓语为非延续性动词，表示“自从动作开始以来有多久了”；若从句的谓语为延续性动词，表示“自从动作结束/完成...有多久了”，常译为“自从不...有多久了”。

It is three years since the war broke out.战争爆发以来，有三年了。

It is twenty years since I've seen her. 我已经二十年没见她了。

五、every time, each time, next time, the first time, any time, all the time 的用法这些短语用来引导时间状语从句，表示“每当..；每次...；下次...”等。

高考It +be+ 时间+ 从句”结构总结一在“It +be+ 时间+ 从句”结构中，引导从句的从属连词有before, that, since, until （till ）, when 等。

这一结构是近几年高考常考的知识点，现将它们的用法小结如下：一、It +be （not ）+ 时间段+before 从句。

其中的主句是肯定式时，意为“过多长时间才……”；主句是否定式时，意为“没过多久就……”。

例如：1. It was not long before the whole country rose and drove the Austrian soldiers from their homeland. 不久，全国人民便奋起反抗，把奥地利军队从他们的国土上赶了出去。

2. It may be five or six years before the new medicine is tested on human beings.要过五六年时间这种新药才能在人身上做试验。

3. It was two months before he designed the bridge. 过了两个月，他设计出了这座桥梁。

二、It +will be （was ）+ 时间段+until 从句若主句中用一般将来时，则从句中用一般现在时，意思是从现在起到从句中谓语动词表示的动作发生时还有多长时间；若主句中用一般过去时，则从句中也用一般过去时，意思是从过去某一时间起到从句中谓语动词表示的动作发生还有多长时间。

例如：1. It will be ten days until my birthday comes. 到我生日还有十天。

2. It was only five minutes until her husband came back from work.当时离她丈夫下班只有五分钟了。

注意：结构“一”与结构“二”在肯定句中几乎可以通用。

It …+点时间/段时间+before…诠释高中英语中,before句式,相似性强,考生易混淆,究其用法,现小结于后,敬供商榷;1. It was / will be + 段时间+ before …在“It was / will be + 段时间 + before 从句”结构中,before是从属连词,表示“……才；……就”,引导时间状语从句;例：It was just 3 days before the book was published.三天后那本书就出版了;例：It will be five years before we meet again.五年后我们才会在见面;2. It wasn’t long before …/ It won’t long before …在“It wasn’t long before从句”结构中,before是从属连词,表示“不久以后就……”；而“It won’t long before从句”结构中,before是从属连词,意为“不久就会……”,引导时间状语从句;例：It wasn’t long before he came home.他不久后才很快回到了家里;例：It won’t long before you get well again.不久你就可以恢复健康了;3. It be + 点时间+ before …在“It be +点时间 + before从句”结构中,before是从属连词,表示“在……之前；时间是……”,引导时间状语从句;例：It was 4:00 before he came to see you.他是四点后来看你的;4. It be + 点时间+ when …在“It be +点时间 + when从句”结构中,when是从属连词,表示“当时是……”,引导时间状语从句;例：It was 4:00 when he came to see you.他来看你时,已是四点了;5. It be + 段时间+ since …在“It be +段时间 + since从句”结构中,since是从属连词,引导时间状语从句;若从句中谓语动词是短暂性动词,表示“自从……以来有多久了”；若从句中谓语动词是延续性动词,则表示“多久不……了”;例：It was two years since I joined the League member.我入团已三年了;join是短暂性动词例：It was many years since I enjoyed myself like this.我已有多年没有像这么开心了;enjoy是延续性动词6. It be + 时间+ that …在“It be +时间 + that从句”结构中,构成强调句,表示“就是……时间才……”;例：It was two years later that I came back from abroad.正是两年后我才回国的;7. It is / will be + 段时间+ until …在“It is / will be +段时间 + until从句”结构中,until是从属连词,引导时间状语从句,表示“过了要过多久才……”,until相当于before;例：It would be 10 years until / before he knew the truth.十年后他才得知真相;温馨提示1until用于肯定句,表示“直到……为止”,谓语动词一般是延续动词,常见的有stay, work, study, play等,表示动作一直延续到until所表示的时间为止;例：Tell him to stay up until I get back..告诉他,等我回来后再去睡;2until用于否定句,表示“在……之前；直到……才”,谓语动词一般是终止性动词,常见的有come, arrive, leave, die等,表示动作到until所表示的时间时才发生;例：They won’t come to any decision until they had a chance to discuss it wholly.等有机会全面讨论这个问题后才定夺;综合上述,句子结构千变万化,规则众多,用法奇特,但只要根据已有的学习经验和知识水平分析句子,理解用意,进一步进行信息整合,推理判断,便可找到更新的理解办法或途径,这样,无论多么难的句子都可以一一化解了;经典演练1. It was _____ he came back from Africa that year ____he met the girl he would like to marry.A. when; thenB. not; untilC. not until; thatD. only; when2. --- Have you know Dr. Jackon for a long time--- Yes, since she ____ the Chinese Society.A. has joinedB. joinsC. had joinedD. joined3. --- Did his father come back early last night--- Yes, it was not yet eight o’clock ___ he arrived home.A. beforeB. whenC. thatD. until答案与解析1. C 考查强调句与时间状语从句辨析;句意：正是他那一年从非洲回来时,他才遇到了他的确想要结婚的那位姑娘;此处应是强调句型,被强调的对象是“not until he came back from Africa that year ”,不是时间状语从句,而选项A,B和D项不合要求,故C项正确;2. D 考查since时间状语从句;句意：自她加入汉语协会以来;据语境分析,此处since表示“自从……以来”,而选项A,B和C均不合语义,故D项正确;3 B 考查when时间状语从句;句意：当他回到家里时,还不到八点;据语境分析,此处it指时间,when引导时间状语从句,表示“当……时候”,而选项A,C和D均不合语义,故B项正确;能力提升1. --- How long do you think it will be ____ China sends a manned spaceship to the moon--- Perhaps two or three years.A. whenB. untilC. thatD. before2. It was some time later ___ we realized two or three years.A. untilB. beforeC. thatD. since3. How long is it ___ we last saw each other in ShanghaiA. sinceB. beforeC. untilD. that4. That was really a special evening, it’s years ___ he enjoyed himself so much.A. whenB. thatC. beforeD. since5. It seemed only seconds ___ the boy finished washing his face.A. whenB. beforeC. afterD. since6. --- What did she want to know, Tom--- She wondered ____ we could complete the experiment.A. when was itB. it was when thatC. it was whenD. when it was that7. Was it in 1939 ___ the Second World War broke outA. thatB. whenC. untilD. since8. It was two years ___ I began to learn English.A. whenB. sinceC. beforeD. that9. It was not until dark ___ he found ___ he thought was the correct way to solve the problem.A. that; whatB. that; thatC. when; whatD. when; what答案与解析考查before时间状语从句;句意：--- 你认为中国多少时间后才能把宇宙飞船发射到月球上呢--- 或许两三年吧;据语境分析,此处before引导时间状语从句,表示“在……之前,……才”,而选项A,B和C均不合语义,故D项正确;考查强调句与时间状语从句辨析;句意：就是一段时间以后我们才能弄清事实的真相;据语境分析,此处强调“some time later”, It be …that …构成强调句式,而不是时间状语从句,而选项A,B和D均不合句式要求,故C项正确;考查since时间状语从句;句意：我们最后一次自在上海见面后有多长时间了呢据语境分析,此处应是since引导时间状语从句,表示“自……以来”,而选项B,C和D均不合语义,故A项正确;4. D 考查since时间状语从句;句意：那是一个特别的晚上,已有多年没有这么开心了;据语境分析,此处应是since引导时间状语从句,表示“自……以来”,而选项A,B和C均不合语义,故D 项正确;5. B 考查before时间状语从句;句意：好像没大一会儿,那个小孩就把脸洗完了;据语境分析,此处应是before引导时间状语从句,表示“….才”,而选项A,C和D均不合语义,故B项正确;6. D 考查强调句与时间状语从句辨析;句意：--- 她到底想知道什么,Tom--- 她想知道我们完成这项实验的时间;据语境分析,此处应是强调句,被强调的对象是“when”,又因放在she wondered之后,随之构成宾语从句,将when提出以平衡句子,表示“….时候”,而选项A,B和C均不合要求,故D项正确;7. A 考查强调句与时间状语从句辨析;句意：就是在1939年爆发的第二次世界大战吗据语境分析,此处应是强调句型,被强调的对象是“in 1939”,不是时间状语从句,而选项B,C和D均不合要求,故A项正确;8. B考查since时间状语从句;句意：我自学英语以来,有两年时间了;据语境分析,此处应是since引导时间状语从句,表示“自……以来”,而选项A,C和D均不合语义,故B项正确;9. A 考查强调句与时间状语从句辨析;句意：直到天黑时,他才发现他所想到的正是解决这个问题的有效途径; 据语境分析,此处应是强调句型,被强调的对象是“not until dark”,又在he found后跟了一个what引导的宾语从句,不是时间状语从句,而选项B,C和D均不合要求,故A 项正确;be +时间段＋before...过了多长时间才.：It was two days before he knew.过了两天他才知道.It was three years before he came back from abroad.过了三年他才从国外回来.be+ 时间点＋when...当.时候,时间是.：It was six when he arrived.当他到达时,时间是6点钟.is / has been +时间段＋since...往往用非延续性动词自从……以来到现在已有多久,做.已经多长时间了：It is / has been five years since he died.他已经死了5年了.is three years since they got married.他们已经结婚三年了.It is three years since they were married.他们已经离婚三年了.若since引导的状语从句的谓语动词是持续性动词或表示状态动词的过去时时,则从句表示的时间是“从动作或状态结束时算起”.再如:It has been quite some time since I was last in London.我上次离开伦敦至今颇有一段时间了. won't be long before...:不久.It won't be long before we meet again.我们不久会再见面.。

It+be+……+that/since/before/when用法辨析1.it was+ (时刻，或时间点）+ when sth. happened。

当某事发生时,是几点钟或哪一年如：It was 1997 when Hongkong returned to China。

It was five o’clock when we arrived at the small mountain village。

对比强调句型：It was at five o’clock that we arrived at the small mountain village。

It+ is/ was+…+that…多用于强调。

判断方法如下：去掉it、be和that，余下的部分仍是一个完整的句子,这样的句子一定是强调句。

2.it was+一段时间+ before sth happened。

过了一段时间之后,某事才发生了.如：it was two years before Macao returned to China.it will be +一段时间before sth。

happens.要过一段时间之后,某事才会发生。

或不用过多久，某些就将发生：it won't be long before sth。

happens。

It won’t be long before you see him again。

没过多久就…It was long before they escaped from the prison。

过了很久才….3。

it is (=has been)+一段时间since sth。

happened。

自某事发生以来,（时间）已经过去.。

了。

如：It is 11 years since Hongkong returned to China.香港回归已经有11年了。

若从句中的动词是终止性动词，意为：“从开始……多久了”例如：It has been five years since she left home.(她离家已经十五年了）It was four years since he had died.（到当时为止，他已死去四年了）若从句中的动词是延续性动词，意为：“不做某事已有多久了”例如：It is two days since she was ill.（她病好了两天)It is two years since he studied English。