2021届高考英语通用版一轮复习考点专讲：考点27时间状语从句学案

考点27 时间状语从句
高考频度：★★★★★


考向一 when/while/as引导的定语从句
一、when引导的时间状语从句
1. when引导的时间状语从句，其动词既可以是延续性动作的动词，也可以是瞬间性动作的动词，而且可以表示主句的动作和从句的动作同时发生，或者从句的动作发生在主句的动作之前。
When you apply for a job, you must present your credentials. 当你申请工作时，你必须递交你的有关证件。（同时）
When the students heard the teacher’s footsteps, they all atopped talking. 当学生们听到老师的脚步声时，他们都停止了讲话。（从句动作发生在前）
2. when还可表示just then（正在那时，突然）的意思，此时其所引导的从句只放在主句之后。
be about to do ... when ... 正要去做某事，突然……
be doing ... when ... 正在做某事，突然……
be on the point of doing ... when ... 正在做某事，突然……
We were about to start when it began to rain. 我们正要动身，突然天下起雨来。
The game had hardly/scarcely/barely begun when it started raining. 比赛刚刚开始就下起雨来。
二、while引导的时间状语从句
while表示＂在某一段时间里＂或＂在……期间＂，其所引导的从句的动作是延续性的，并侧重表示和主句的动作同时发生。
When the teacher paraphrased the text in English, the students listened attentively and took notes. 当老师用英语解释课文时，学生们聚精会神地听并做着笔记。
I can learn while I work. 我可以边工作边学习。
三、as引导的时间状语从句
as引导的时间状语从句其动词的动作是延续性的，而且侧重表示主句和从句的动作交替或同时发生，译为＂一边……，一边……＂或＂随着……＂。
We were having breakfast as she was combing her hair. 她梳头时我们在吃早饭。
It will warm up a little bit on Sunday as the cold front passes. 寒流一过，星期日就会有点暖意了。

1.（2016·全国新课标卷III·语法填空）Over time, 45 the population grew, people began cutting food into small pieces so it would cook more quickly.
【参考答案】as/when
【答案解析】考查时间状语从句。句意：随着人口的增长，人们开始把食物切成小块，这样可以煮得快一点，这里是时间状语从句，when意为＂当……的时候＂，后跟长动作或短动作，故填as／when。
2.（2016·四川卷·语法填空）The mother held the baby in her front paws much the way a human does. 46 it cried, she rocked it back and forth and gave it little comforting pats.
【参考答案】When/If
【答案解析】考查时间状语从句。句意：如果或当它哭的时候，她会前后摇动。故填When/If。
考向二before引导的时间状语从句
一、before的常见意思
1. before＂在……之前＂。
I have finished my dissertation before my supervisor went abroad. 在我的导师出国之前，我已完成了我的学位论文。
I’ll be back before you have left. 你离开之前我就会回来。
2. before＂……之后才＂。
It may be many years before we meet again. 可能要过许多年我们才能再见了。
It was three days before he came back. 他三天后才回来。
3. before ＂尚未来得及 ＂
Before she could move, she heard a loud noise, which grew to a terrible roar. 她还没有来得及动弹，就听见有很响的声音，接着就成了可怕的隆隆轰鸣声。 
Before they reached the house, a new great wave came, sweeping down trees, and sweeping them down too. 他们还没到屋子，又一个巨浪打来，冲倒了树，也冲倒了他们。 
4. before ＂要……先……＂
You should be a pupil before you become a teacher. 要当老师，先作学生。 
5. before＂趁……＂
You should do it before it is too late. 趁现在还不算太晚，你应该赶快做它。
二、掌握热点句型用法
1. it was（not）/had done＋一段时间＋before（vt-ed）…＂还要过多久才……（不多久就……了）＂
It was not long before he returned to Beijing. 不久他就回到北京。 
It was long before he married Wei Fang. 过了很久他才娶魏芳。 
2.it will（not）be＋一段时间＋before（一般式）… ＂还要过多久才……（不多久就……了）＂
It will be long before he goes abroad. 要过很久他才出国。 
3.there is +一段时间+to go（=left）＋before（一般式）... ＂在……之前＂
4.long before ＂不久前＂, 用于一般过去时和完成时中；before long = soon/not long after ＂不久后＂，用于一般将来时和一般过去时中。

1.We need to get to the root of the problem ______________ we can solve it.
A. while B. after C. before D. as
【参考答案】C
【答案解析】考查时间状语从句的连接词。句意：在我们解决问题之前，我们需要找到问题的根源。A. while当……的时候，而；B. after在……之后；C. before 在……之前；D. as正如。根据句意可知选C。
2.It ________ long before we ________ the result of the experiment. 
A. will not be；will know  B. is；will know 
C. will not be；know  D. is；know 
【参考答案】C
【答案解析】句意：不会过很长一段时间我们就会知道实验结果。应使用It was not long before的创新句型It will not be long before，before引导时间状语从句时，从句应用一般现在时代替一般将来时。 
2.Scientists say it may be five or six years ________ it is possible to test this medicine on human patients. 
A. since  B. after  C. before  D. when 
【参考答案】C
【答案解析】该句型也是It was not long before的创新句型。句意：科学家说也许再有5年时间这种药就可以在人类身上做实验了。
考向三as soon as/once/directly/the instant等引导的时间状语从句
as soon as 是最常见的表示＂一……就……＂的从属连词，其他连词还有once（一旦），directly（老式英国英语），immediately（主要用于英国英语），instantly，the instant (that)，the minute(that) ，the moment(that)等，它们通常都可与as soon as换用。
As soon as we got home, the telephone rang. 我们一到家，电话就响了。
I recognized her immediately I saw her. 我一看见她就认出她来了。
Directly the teacher came in everyone was quiet. 老师一进来，大家就静了下来。
考向四 hardly...when/no sooner...than引导的时间状语从句
hardly/barely/scarcely...when和no sooner...than的意思是＂刚……就＂，它们所引导的从句中的谓语动词通常为过去完成时。
He had no sooner (no sooner had he) arrived home than he was asked to start on another journey. 他刚一到家，就又要他出另一次差。
★ hardly/barely/scarcely和no sooner置于句首时，从句要倒装。
No sooner had the words been spoken than he realized that he should have remained silent. 这些话刚一出口，他就意识到自己应该保持沉默。
考向五since引导的时间状语从句
在含有since引导的时间状语从句的复合句中，从句的谓语动词通常为一般过去时，主句的谓语动词通常为现在完成时。
We’ve never met since we graduated from the college. 大学毕业后我们就再没见过面。
Great changes have taken place since you left. 你走了以后，这里发生了巨大的变化。

1.（2017·天津卷·完形填空）She had been talking to her mother about the lives of homeless people 42 they first saw the homeless man.
A. since B. unless C. although D. as
【参考答案】A
【答案解析】考查连词。A. since 自从B. unless 除非C. although尽管D. as因为。句意：自从他们第一次看到无家可归的人，Hannah就一直在跟她的妈妈说流浪者的生活，根据句意可知选A。
2.I have heard a lot of good things about you I came back from abroad.
A. since B. until C. before D. When
【参考答案】A
【答案解析】考查状语从句。题干中主句谓语动词用现在完成时，从句中谓语动词用一般过去时，由题干意思可知所填词意思是：自从，因此用since引导时间状语从句。句意：自从我从国外回来后，我已经听说了很多关于你的好事。
考向六till/until引导的时间状语从句
till和until同义，作＂直到……时(为止)＂解，till多用于非正式文体，until多用于句首。
Donald will remain in college until (till) he finishes his Ph.D course. 唐纳德将留在学校直到完成他的博士学位课程。
I won’t go with you until (till) I finished my homework. 等我做完作业我才和你一起去。
注意：
not until 置于句首，主句要倒装。
Not until 4:00 in the morning can he fall asleep.
直到凌晨4点他才睡着。(He can’t fall asleep until 4:00 in the morning.)
Not until he returned did we have supper.
直到他回来我们才吃晚饭。 (We didn’t have supper until he returned.)

(2017·北京卷·单项填空)If you don’t understand something, you may research, study, and talk to other people _______ you figure it out.
A. because B. though C. until D. since
【参考答案】C
【答案解析】A. because 因为 B. though尽管 C. until 直到 D. since自从。句意：如果你无法理解某个东西，你可能会去研究，学习并和他人探讨直到你解决为止，根据句意可知选用until“直到”，选C。
考向七each time/every time等引导的时间状语从句
这类连词主要有every time(每次)，each time(每次)，(the) next time(下次)，any time(随时)，(the) last time(上次)，the first time(第一次), by the time(当……的时候)。如：
You can call me any time you want to. 你随时都可以给我打电话。
Each time I went there, I saw him working. 我每次去那儿都看见他在工作。
Every time I see her I'll think of it. 每次我看到她，我就想起这事。
Next time you come in, please close the door. 下次你进来，请关门。
He didn't tell me the last time I saw him. 我上次见到他时他没告诉我。
The first time I heard about the firm closing down was when George told me.
我最初听到公司倒闭的消息是乔治告诉我的。
By the time, he was taken to the hospital he was nearly dead.
他被送到医院时已经几乎不行了。
注意：every time, each time, any time前不用冠词，(the) next time, (the) last time中的冠词可以省略，而the first time中的冠词通常不能省略。


题组一 能力过关
I．单项填空
1. It was 3 in the morning ___________ the earthquake happened. Hundreds were killed, with a lot ___________ in the collapse.
A. that；buried B. when；buried
C. that；burying D. when；burying
2. __________ it comes to traffic rules, I often come across such cases __________ the local drivers obviously know them but won’t follow them.
A. If；why B. When；which
C. Once；as D. When；where
3. Every time __________ they met, they would talk excitedly for several hours about the schoolmates and incidents __________ they still remembered in the primary school.
A. that；who and which B. when；that
C. /；that D. when；which
4. Many people have heard of the ＂brain drain＂. This is ___________ happens __________ people with good skills and a good education move to other country for study or work, often at great expense to their home countries.
A. which；when B. what；that
C. what；when D. why；when
5. —Glad to see you, Kate.
—Oh, my God. It’s been 20 years ___________ we last saw each other.
A. when B. before
C. after D. since
6. He smiled politely ____________ Mary apologized for her drunken friends.
A. as B. if
C. unless D. though
7. ___________ the poem a second time, the meaning will become clearer to you.
A. Having read B. While reading
C. If reading D. When you read
8. The police set about arresting the suspect ___________ they found enough evidence to prove him guilty.
A. immediate B. as long as
C. the moment D. as far as
9. The police had to employ force ___________ the crowd got out of control.
A. the instant B. at the instant
C. in an instant D. for an instant
10. If individuals are awakened ___________ they begin a dream phase of a sleep, they are likely to become irritable even though their total amount of sleep has been sufficient.
A.as if B. now that
C. each time D. first time when
II.语法填空
Eating organic food will not make you healthier, according to researchers at Stanford University, although it could cut your 　1　(expose) to pesticides(杀虫剂).They looked at more than 200 studies of the content and 　2　(associate) health gains of organic and non-organic food. Overall, there 　3　(be) no difference in the nutritional content, although organic food was 30% less likely 　4　(contain) pesticides.
The researchers looked at 17 studies comparing people who ate organic food 　5　those who did not and 223 studies 　6　compared the levels of nutrients, bacteria and pesticides in various food. However, none of the human studies ran for longer than two years, 　7　(make) conclusions about long-term 　8　(outcome) impossible. And all of the available evidence was 　9　(relative) weak and variable, which the researchers said was unsurprising because of all the different variables.
Dr Crystal Smith-Spangler, the lead researcher, said "Some believe organic food is always healthier and more nutritious. But as 　10　matter of fact there isn’t much difference between organic and conventional food, if you’re an adult and make decisions based simply on your health."
题组二体验真题
1.（2018·北京卷·完形填空）To think he is sleeping on the streets tonight 26 he could have stolen the money and paid for a place to stay in.
A. when B. if C. where D. because
2.(2016·天津)______ the average age of the population increases, there are more and more old people to care for.
A. Unless B. Until
C. As D. While
3.（2016·浙江）______online shopping has changed our life , not all of its effects have been positive.
A. Since B. After
C. While D. Unless
4.(2015·天津) We need to get to the root of the problem______ we can solve it.
A. while B. after
C. before D. as



题组一 能力过关
I．单项填空
1. B
【解析】考查连词和非谓语动词。根据句子结构可知the earthquake happened是时间状语从句，应用when引导；第二空动词bury应用非谓语动词作a lot的宾语补足语，且与a lot之间是逻辑上的被动关系，故用buried，选B项。
2. D
【解析】考查时间状语从句和定语从句。句意：当说到交通规则的时候，我经常遇到这样的情况，当地司机很显然知道这些规则，但是不愿意遵守它们。第一空用when引导时间状语从句，when it comes to sth当说到……的时候，第二空引导定语从句，case作先行词表示情况时，用关系副词where。故选D。
3. C
【解析】考查状语从句和定语从句。句意：每次见面，他们都会兴奋地聊上好几个小时关于小学时的同学和事情。every time可直接引导时间状语从句，不需要再加连接词，第二个空为定语从句，当先行词既有人又有物时，关系代词用that，故C项正确。
4. C
【解析】考查表语从句和时间状语从句。句意：许多人都听说过＂人才外流＂。这是当有好技能和好的教育的人搬到另外一个国家学习或工作的时候发生的事情，经常以他们的祖国作为代价。第一空是引导表语从句，从句缺主语，用what引导，第二空是引导时间状语从句，用when引导。故选C。
5. D
【解析】考查连词。句意：——凯特，很高兴见到你。——天啊！自从我们上次相见已经20年了。A. when＂当……的时候＂；B. before＂在……之前＂；C. after＂在……之后＂；D. since＂自从＂。since引导时间状语从句，从句的时态用一般过去时，而主句中用现在完成时。故选D。
6. A
【解析】句意：当玛丽为她醉酒的朋友道歉的时候，他有礼貌地笑了笑。此处as引导时间状语从句，表示＂当……的时候＂。if＂如果＂，引导条件状语从句；unless＂除非＂，引导条件状语从句；though＂尽管＂，引导让步状语从句。
7. D
【解析】考查时间状语从句。句意：当你再次阅读这首诗的时候，它的意思将变得更清晰。逗号后面的句子主语是the meaning，前面动词是read，the meaning不是read的逻辑主语，不能用非谓语动词作状语，要用when引导时间状语从句。故选D。
8. C
【解析】the moment意为＂一……就……＂，引导状语从句。句意：警察一掌握足够的证明他有罪的证据后就开始着手逮捕这个嫌疑犯了。
9. A
【解析】考查连词短语。句意：人群一旦失控，警察不得不动用武力。the instant是连词短语，意为＂一……就＂；at the instant在那个瞬间；in an instant很快；for an instant一会儿。故选A。
10. C
【解析】考查时间状语从句。句意：如果人们在一个开始做梦的睡眠阶段被吵醒，他们可能变得急躁，即使他们的睡眠总量是足够的。as if 表示＂好似＂；now that表示＂既然＂；each time表示＂每次＂，多用来引导时间状语从句；first time when表示＂第一次当……的时候＂，故选C。
II.语法填空
【文章大意】本文是一篇说明文。研究表明，吃有机食物并不会让你更健康。
1.exposure
【解析】考查名词。据斯坦福大学的研究者所说，吃有机食物不会让你更健康，尽管它能让你少接触杀虫剂。根据空前的"your"及空后的介词"to"可知，此处应填名词。exposure"遭受，接触"。
2.associated
【解析】考查形容词。此处指他们研究了有机食物和非有机食物的所含之物和相关的健康效益。空处作定语修饰名词短语"health gains"，故应填形容词。associated"有关联的，相关的"。
3.was
【解析】考查时态和主谓一致。根据句中的"was"及此处陈述的是过去研究的结果可知，此处应用一般过去时;又因主语为"no difference"，故谓语动词应用第三人称单数。故填was。
4.to contain
【解析】考查非谓语动词。be likely to do sth.是固定结构，意为"有可能做某事"，故此处应填不定式to contain。
5.with
【解析】考查介词。此处指研究者将吃有机食物的人和不吃有机食物的人作比较。compare...with... 是固定搭配，意为"比较……，与……相比"。
6.that/which
【解析】考查定语从句。分析句子结构可知，空处在此引导定语从句，且在从句中作主语，先行词是"223 studies"，故填关系代词that/which。
7.making
【解析】考查非谓语动词。分析句子结构可知，句子中已有谓语动词"ran"，故此处应填非谓语动词。又因动词"make"与其逻辑主语"none of the human studies"之间是主谓关系，故此处应用现在分词作结果状语。
8.outcomes
【解析】考查名词复数。outcome"结果，后果"为可数名词且其前无限定词修饰，故此处应用其复数形式outcomes。
9.relatively
【解析】考查副词。此处应用副词修饰形容词"weak and variable"，故填relatively"相对地"。
10.a
【解析】考查冠词。as a matter of fact"事实上"是固定搭配。故填不定冠词a。
题组二 体验真题
1.A
【解析】考查状语从句引导词。A. when在……情况下，既然；B. if如果；C. where表地点；D. because因为。在Tom本来可以偷了钱去支付一个可以睡觉的地方的情况下，他仍然选择了露宿街头（没有偷钱）。所以Mr. Anderson对Tom的行为感到很惊讶。A选项正确。
2.C
【解析】句意：随着人口平均年龄的增长，越来越多的老人要照顾。unless除非；until直到；as因为，正如，随着；while虽然，然而，当……时候。根据语境，故选C。
3.C
【解析】句意：尽管网上购物已经改变了我们的生活，单数不是所有的影响都是积极的。while引导让步状语从句，意为＂尽管，虽然＂；since既然，自从；after在……之后；unless除非。故选C。
4.C
【解析】句意：在我们解决问题之前，我们需要找到问题的根源。while当……时候，而； after在……之后； before 在……之前； as正如。根据句意可知选C。