when和before句型
when,before,since句型
When, before, since 句型1. when 的句型(1) be doing sth….when…正在做某事时…突然…We were swimming in the pool when it began to rain.We were studying English when he came in.(2) be about to do sth…. when …正要做…突然…We were about to leave when he came in.(3) had hardly/scarcely/just done sth…. when…刚…就…We had hardly finished the work when he came in.(4) when=now=since 表示“既然”It was foolish of you to take a taxi when you could get there in 5 mins. Now you are here, you’d better stay.2. before 句型(1) it will be + 时间段+ before sb. do sth. 再过多久…才…It was +时间段+before sb. did sth. 过了多久…才…It won’t be long before sb. do sth. 过不了多久某人就会…Eg. It will be 1 year before we go to college.It was 4 years before we graduated.(2) 主语+had done/did sth.+时间段+ before +did sth. 过了…才e.g. We had sailed for 4 days before we found the island.We waited a long time before the train arrived．我们等了很长时间火车才到。
before与ago、when,while,as区别
一、before与ago的区别1.ago表示“从现在起的若干时间以前”，意思是“距今……以前”，需和过去时或过去进行时连用。
before泛指“从过去起的若干时间以前”，意思是“距过去某时……以前”“与其……（毋宁）”，常和完成时连用，尤其在间接引语中，如：I visited him three days ago, but he had gone to Shanghai a week before．我三天前去访问他，但他已与那时的一周前到上海去了。
His parents died ten years ago．他父母十年前都去世了。
He said that his parents had died ten years before．他说他父母亲十年前都去世了。
I have never been there before．我以前从来没有去过那里。
2.如果不具体表明多少时间以前，只用before不用ago，意为“从前、以前”。
before仍以副词的形式置于被修饰语后，常与完成时候过去时连用。
如：Have you seen this film before?He asked me whether I had been to the Great Wall before．3.表示在某一点时间或事件以前时，只用before不用ago，这种用法是将before当作介词或连词使用。
ago不具有这一功能。
如：They will come back before six o’clock．It is hoped that this will be finished before the year 1995．希望这件工作将在1995年以前完成。
另外，before在句中的含义较多。
不少句子中，before虽然引导的也是一个时间状语，但是译成汉语时却不必译为“在……以前”。
a.如果before引导的从句动作发生得晚或慢，可译成“……才”。
come短语,before,when
come短语,before,whenBefore的翻译连词before是一个常用词，在状语从句中一般译为“在。
之前”，但在很多情况下，由于英汉两种语言的差异，before的翻译极为复杂，不能一律译为“在。
之前”。
例如：It was an awkward moment, for he needed to compose himself before he could greet Charlotte, but he was clearly eager to greet her before he could compose himself.这一刹那是尴尬的，他需要先使自己镇定一下，才能向夏洛蒂问好。
但是他还没来得及镇定下来。
显然就迫不及待地先向她致意了。
Before在这段文字中出现了两次，两处有不同的译法，即“先。
才能。
”和“还没来得及。
就”。
在含表示时间的连词before引导的状语句中，有两个主要动词，表示两件事情一前一后发生，或说甲在乙先，或说乙在甲后，视具体情况用汉语确切而通顺地表达出来，并突出应强调的一方。
因此，before的翻译很灵活，它所对应的汉语极为丰富，不能拘泥于一种译法。
以下是一些最常用的译法。
1. before译为“（在）。
之前”Before the rooster crows, you will say three times that youdon't know me.在公鸡叫之前，你要说三次你不认识我。
You must not count your chickens before they are hatched.小鸡尚未孵出之前不能算数。
2. before译为“来不及。
”、“还没有来得及。
就”Before he could press the trigger, the plane had gone up again.他还来不及扣动板机，飞机又飞高了。
Before we could stop him, he had rushed on to a potato plot and dug up one of the potatoes. 我们还来不及阻止他，他已经飞奔到一块土豆地里，挖出了一只土豆。
when, if, before, until从句
when if before until引导的从句由一个主句和一个或多个从句构成的句子叫复合句。
主句是复合句的主干部分，从句是修饰主句或主句的某个成分的。
从句不能单独成句，但具有主语和谓语，须由关联词引导。
根据从句在主句中充当不同的成分，可分为不同的从句，例如，主语从句、宾语从句、表语从句、同位语从句、定语从句、状语从句等。
由when, if, before, until引导的从句一、when引导的时间状语从句(1) when引导时间状语从句时，表示“当……的时候”① when既可以指时间段也可指时间点Her brother was very fat when he was a child. 她哥哥小时候很胖。
They were talking when the teacher came in.老师进来的时候，他们正在讲话。
② when从句中既可用延续性动词又可用非延续性动词You should keep your room clean and tidy when you live here.在你住在这里的时候，你应该保持你房间干净、整洁。
When he arrives, he’ll tell us about the match.他回来的时候就会告诉我们比赛的情况。
③ when从句动作既可和主句的动作同时发生又可在主句的动作之前或之后发生Mary was doing her homework when her father was reading newspapers.玛丽的爸爸在看报纸的时候她正在做作业。
I’ll call you when I get to the airport. 我一到机场就给你打电话。
二、if引导的条件状语从句条件状语从句表示主句动作发生的条件，条件有真实和非真实两种。
if引导条件状语从句时，意为“如果，假如”，表示在某种条件下，某事很可能发生。
if除了引导条件状语从句，还可引导宾语从句。
时间状语从句用法
概念：在复合句中，由时间连接词引导的状语从句叫做时间状语从句。
(在复合句中，要注意主句和从句的时态大多都要保持一致。
） 1.由when, while, ,just ,just as, as，after, before, since, until, as soon as,引导的时间状语从句。
例如：When you think you know nothing, then you begin to know something.当你以为自己一无所知的时候，你就是在开始知道一些事物了。
When truth is buried under the ground ，it grows, it chokes, it gathers such an explosive force that on the day it bursts out , it blows up everything with it.当真理被埋在地下的时候，它在生长，它感到压抑，它蓄存着这么一种爆炸性力量，一旦冒出，它就会炸破一切！Strike while the iron is hot. 趁热打铁。
You can feel the air moving as your hand pushes through it.当你的手在空气中挥动的时候，你就能感觉到空气在流动。
Our headmaster laughed as she spoke. 我们的校长边谈边笑。
主要时态：主现从不现；主过从四过；主将从现。
when, while和as的区别when引导的从句的谓语动词可以是延续性的动词，又可以是瞬时动词；动作既可以和主句的动作同时发生，又可以在主句的动作前后发生。
并且when 有时表示“就在那时”。
例如：When she came in, I stopped eating.她进来时，我停止吃饭。
(瞬时动词)When I lived in the countryside, I used to carry some water for him.当我住在农村时，我常常为他担水。
when-before-since区别及用法
storm started.
AA.. wwhen
B. while C. until
D. before
2. (02上海) He was about to tell me the secret ______ someone
patted him on the shoulder.
A. as
B. until
C. while D. whheenn
when,before,since句型归纳
1、when 句型： (1) be doing sth…when…
He was still smiling when the door opened and his wife came in.
他正笑着的时候门突然开了，他妻子走了进来 。
(2) be about to do sth…when… We were about to start when it began to rain. 我们刚要出发，天就开始下雨了。
It is 5 years since he left Beijing . 他离开北京5年了
It has been 3 years since he came back from abroad.自从他回国已经三年了
3.since句型
It is/has been＋时间段＋since sb. did… §②§did动作为持续动词（延续性），翻译为 自从不做某事有多长时间
(4)hardly /sceracely…when… (一…就…) He had not/hardly/scarcely fallen asleep when the telephone rang. 他刚要入睡电话就响了。
We had scarcely arrived when he asked us to leave. 我们才刚刚到他就叫我们走了.
(完整word版)when,since,before,that句型
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。
状语从句
状语从句（一）时间状语从句表示时间的状语从句可由1. when ,while, as1) when 句型：(1) Sb. was /were doing sth ---- when(suddenly) sb. did sth.---(2) Sb. was /were about to do sth. ---- when(suddenly) sb. did sth.---(3) Sb. had just done sth. ---- when(suddenly) sb. did sth.---1）She had just finished her homework her mother asked her to practice playing the piano yesterday.2）(短改）Jasmine was holidaying with her family in a wildlife park while she was bitten on the leg by a lion.2.There’s no way of knowing why one man makes an important discovery ______another man, also intelligent, fails.3) time goes by, computers are playing an increasingly important role in our daily life.2. until /tillI didn’t leave there until he came back.Not until .It was not until .It was not until midnight they reached the camp site.3. immediately ,instantly, directly /as soon as /the moment ,the minute ,theinstant /on doing Hardly /Scarcely ......when....../ No sooner ....thanHardly had sb. done sth. --- when sb. did sth. –The moment I saw him, I gave the book to him.（短改）He had no sooner finished his speech when the students started cheering.4. before 句型：(1) before sb can/ could … 某人还没来得及……例：Someone called me up in the middle of the night，but they hung up ____ I could answer the phone.(2) It will(would/may) be +时间段+ before(3) It was +时间段+ before1. I’m sorry you’ve been waiting so long，but it’ll still be some time ____Brian gets back.2.John thinks it won’t be long ______ he is ready for his new job.3. It was a busy morning, about 8:30, when an elderly gentleman in his 80s came to the hospital.I heard him saying to the nurse that he was in a hurry for appointment （约会）at 9:30.The nurse had him take a 36 in the waiting area, 37 him it would be at least 40 minutes 38 someone would be able to see him .36.A.breath B. test C. seat D. break37.A.persuading B. promising C. understanding D. telling38. A. if B. before C. since D. after5. since 句型：(1) S + 现在完成式since + S + 过去式例句：He has worked very hard since he went to senior high school.(2) It is/has been + 时间段--- + since + S + 过去式As it reported, it is 100 years ______ Qinghua University was founded.(短改）Most people can quickly get help from a doctor or go to a hospital since they are ill. (全国卷)6. time 句型：(1) the first time 例：I thought her nice and honest the first time I met her.(2) It is ／was the first／last／second ／third time ＋从句（完成时态）例：This is the first time I have been here 这是我第一次到这儿。
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Hale Waihona Puke 正在做某事时突然… 1. be doing sth.…when …正在做某事时突然 正在做某事时突然 Eg. He was still smiling when the door opened and his wife came in. 正要做某事时突然… 正要做某事时突然 2. be about to do sth. …when … Eg. We were about to start when it began to rain. 3. had not/hardly/just done sth. when … Eg. He hadn’t/hardly fallen asleep when the telephone rang. 4. had just done …when … Eg. He had gone to bed when the telephone rang.
before句型 句型
4. had not done…before不到 就… 不到…就 不到 Eg. We hadn’t walked a mile before he felt tired. 5. It was not +一段时间 一段时间+before… 一段时间 不多久就… 不多久就 Eg. It wasn’t 2 years before he left the country.
when句型 句型
before句型 句型
1. It will be +时间 时间+before …还有多长时间 还有多长时间… 时间 Eg. It will be 4 years before he graduates. 2. before sb… can/could…某人还没来得及 某人还没来得及… Eg. The phone rang in the middle of the night, and the hung it up before I could answer it. 3. had done some time before…才… 才 Eg. They had sailed three days and three nights before they saw land. .