1、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 th
2、e 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
3、+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 oclock 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 was(not)+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
4、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
5、.(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:Its 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,
6、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:Its 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 oclock that we heard the noise.例 2:It was 3
7、 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 oclock 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 cl
8、ock 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 oclock _ 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 coul
9、d 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
10、 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 wasnt long before I found a job.我没花多少时间就找到了工作。It wont 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 wont 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。 Weve 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,