状语从句
让步状语从句
1．(·四川卷)He is so busy．He cannot afford enough time with his son ________he wants to．
Α．even ifΒ．as if
C．because D．before
解析：句意为：他那么忙。他抽不出足够的时间来陪儿子，尽管他想去陪他。本题考查让步状语从句。Α．尽管；Β．好像；C．因为；D．在……之前。
答案：Α
2．(·辽宁卷)One can always manage to do more things，no matter________full one’s schedule is in life．
Α．how Β．what
C．when D．where
解析：句意为：一个人总能设法做更多的事情，无论他生活中的时间安排得有多满。考查状语从句。no matter how引导让步状语从句。
答案：Α
时间状语从句
3．(2013·陕西卷)I have heard a lot of good things about you________I came back from abroad．
Α．since Β．until
C．before D．when
解析：句意为：自从我从国外回来，我听到了很多关于你的好消息。考查状语从句。空格前的句子使用了现在完成时，空格后是过去时，符合since“自从……(至今)”的用法。
答案：Α
4．(·山东卷)________I have to give a speech，I get extremely nervous before I start．Α．Whatever Β．Whenever
C．Whoever D．However
解析：句意为：无论何时我必须演讲，在开始前都会感到特别紧张。本题考查状语从句。空格处的引导词在这儿引导让步状语从句，根据句意答案应该是Β。
答案：Β
5．(·安徽卷)It’s much easier to make friends________you have similar interests．
Α．unless Β．when
C．even though D．so that
解析：句意为：当你们有相似兴趣的时候，交朋友就容易多了。本题考查状语从句。Α．除非；Β．当……时候；C．即使；D．以便。根据句意应选Β项。
答案：Β
条件状语从句
6．(·重庆卷)________we have enough evidence，we can’t win the case．
Α．Once Β．Αs long as
C．Unless D．Since
解析：句意为：除非我们有足够的证据，否则我们不能胜诉。本题考查状语从句。unless 除非，相当于if．．．not。once一旦；as long as只要；since既然，自从。
答案： C
7．(·江西卷)—Our holiday cost a lot of money．
—Did it？Well，that doesn’t matter________you enjoyed yourselves．
Α．as long as Β．unless
C．as soon as D．though
解析：句意为：——我们这次度假花了很多钱。——是吗？没关系，只要你们玩得高兴就行。as long as只要；unless除非；as soon as一……就；though 尽管，虽然。
答案：Α
原因状语从句
8．(·山东卷)Mark needs to learn Chinese________his company is opening a branch in Βeijing．
Α．unless Β．until
C．although D．since
解析：句意为：Mark需要学习汉语，因为他的公司正准备在北京开一家分公司。本题考查状语从句。unless除非、如果不，引导条件状语从句；until直到，引导时间状语从句；although尽管，虽然，引导让步状语从句；since由于，因为，既然，在此引导原因状语从句。
答案： D
9．(·重庆卷)—Coach，can I continue with the training?
—Sorry，you can’t________you haven’t recovered from the knee injury．
Α．until Β．before
C．as D．unless
解析：考查连词的用法。句意为：——教练，我可以继续训练吗？——很抱歉，不可以，因为你的膝盖受伤还没有恢复过来。根据句意此处应用引导原因状语从句的连接词as，
故选C 项。
答案： C
地点状语从句
10．(·江苏卷)In the global economy，a new drug for cancer，________it is discovered，will create many economic possibilities around the world．
Α．whatever Β．whoever
C．wherever D．whichever
解析：句意为：在全球经济中，一种治疗癌症的新药，无论是在哪里被研制，都将会在全世界创造很多经济机会。本题考查状语从句。设空处在从句中作状语，故选C项。
答案： C
11．(·四川卷)If you happen to get lost in the wild，you’d better stay________you are and wait for help．
Α．why Β．where
C．who D．what
解析：考查状语从句。句意为：如果你在野外迷路了，最好待在原地，等待帮助。where 引导地点状语从句。
答案：Β
方式状语从句
12．(·湖南卷)Jack wasn’t saying anything，but the teacher smiled at him________he had done something very clever．
Α．as if Β．in case
C．while D．though
解析：句意为：杰克没说什么，但是老师向他微笑，好像他之前做的是明智之举似的。考查状语从句的用法。in case以防；while然而；though尽管，以上三项都不符合句意，故选Α项。
答案：Α
1．as引导让步状语从句时单数名词作表语，其前不用冠词是考生的易错点。
2．熟练掌握when，while和as的用法区别是解决时间状语从句的关键。
3．before的一词多义及各种句式是出错率最高的考点。
4．其他连词的选择在正确把握语境的前提下一般都能够作出正确答案。
高考状语从句考点复习 一状语从句高考的考查特点 1. 试题的设问呈现出交叉和综合的特点 (不同性质的连词; 定语从句和名词性从句的干扰 2. 题干句的情景化增强,句意理解难度提高 二能力要求： 1.了解状语从句的分类情况及各种状语从句中经常使用的连词 2.能够在真实的语境中判定从句与主句的逻辑关系,从而能够使用恰当的连词完成交际. 3.能够辨别同类状语从句中近似连词的用法区别. 三状语从句的定义、功能、分类 定义：在复合句中作状语的从句 功能：状语从句在主从复合句中修饰主句中的动词，形容词或副词，或整个主句 分类：按意义可分为时间、地点、原因、目的、结果、条件、方式、比较、让步等状语从句。 从句的位置放在句首，也可放在句末。放在句首时，从句后面常用一个逗号，放在句末时，从句前一般不用逗号。 ▲ 常见考点： 考点一、主句与从句的时态呼应问题； 考点二、连接词的选择（注意区别几组连接词：while / as / when引导时间状语从句；because / since / as / for引导原因状语从句；if / unless引导条件状语从句；so…that / such…that引导结果状语从句等）； 考点三、状语从句与非谓语动词之间的替换； 考点四、状语从句的倒装结构（hardly / scarcely…when；no sooner…than 等） 考点五、根据从句与主句的逻辑关系选用从属连词；2.根据从属连词的词义。
★四、分类：状语从句按其作用可分为九类。 1．时间状语从句常见的从属连词有：(注意其汉语意义 when, while, as, before, after, since, until (till once as soon as, the moment, the minute, immediately, directly, each/every time, the first time, the last time, next time, by the time, whenever等。例如： Every/Each time I was in trouble, he would come to my help. I thought her nice and honest the first time I met her. 注意：（1）when, while, as的区别： 1when引导从句时，主从句的动作有先有后，也可以同时进行,从句的动作可以是持续性的，也可以是短暂的。如： When I got to the airport, the plane had already taken off. （主先从后）（短暂性） When I lived there, I used to go to the seaside on Sundays. (同时（持续性） When the movie ended, the people went back. （从先主后） 2while侧重主从句动作的对比，且从句的动词必须是持续性的。如： While we were chatting she was looking at the time table on the wall． 3as引导从句时侧重主从句动作同时或几乎同时进行，从句的动作可以是持续性的，也可以是短暂的。如： Sometimes I watch TV as I am having breakfast． 4）when和while还可以是并列连词，意分别为“就在这时”，“然而”。eg. I was having a rest on the sofa when the telephone rang． They were surprised that a child should work out the problem while they couldn’t . 注：并列连词when常用与以下句型中： ①…was/were doing…when…（正在做…突然）②…was/were about to do…when…（刚要做…突然）
高考英语新状语从句知识点真题汇编附答案(1) 一、选择题 1．The sales of houses in our city fell by 40 percent last month, and it will be 48 percent ______ we don’t count low-price houses provided for poor residents. A．as B．unless C．if D．before 2．______ the environmental impacts of larger plastics are well documented, very little is understood about the dangers associated with micro plastics. A．While B．As C．Because D．If 3．All bad things must come to________end, ________ terrible an experience is. A．the; whatever B．an; however C．/; how D．a; what 4．There are other languages that sound extremely different, ________ they’re conveying exactly the same meaning. A．as though B．even though C．so that D．in that 5．The basic model function of the hero seems to remain constant, ______ the precise qualities of hero may vary over time. A．in case B．as if C．so that D．even though 6．_____ I once made some mistakes, I won’t spend a moment of the future regretting what might have been. A．Until B．While C．Unless D．Because 7．Do not make complaints about being left out___you shy away from sharing your joys and sorrow with others. A．when B．unless C．once D．until 8．The young lady rushed into the room _____ she heard the noise. A．right away B．at once C．immediately D．at the moment 9．Under the regulation, restaurants and hotels shall stop offering throwaway items_______customers request them. A．since B．once C．unless D．until 10．______, his ideas was accepted by all the people at the meeting. A．Strange as might it sound B．As it might sound strange C．As strange it might sound D．Strange as it might sound 11．You should take control of your life _________ it is planning coursework or picking a major. A．whenever B．whether C．whatever D．no matter 12．Prince Harry and his wife, Meghan, will give up the name “royal” ____ they withdr aw from official duties and embrace new lives, the couple confirmed on Friday. A．unless B．while C．as D．although 13．_____I had more money, I could buy a car. A．Only if B．If ever C．If only D．Even if 14．—Nowadays some parents keep their children under their wings. These helicopter parents even protect their children from the knowledge ________ they have failed. —Absolutely. They should know that setbacks and failures are part and parcel of adolescent growth.
高考英语新状语从句知识点专项训练及答案(4) 一、选择题 1．____ I look back to those days as a child, I really hope to spare more time to accompany my father. A．However B．Whenever C．Whatever D．Wherever 2．Steve Jobs is a key figure in the computer world _____ he has had a great influence on modern life and technology. A．on condition that B．in case C．in that D．as long as 3．Why do many students stick to private tutoring _____ they could easily master such knowledge at school? A．unless B．before C．after D．when 4．He differed _________ other people __________ he always looked further ahead in his work. A．from; in which B．from; in that C．with; in which D．with; in that 5．All bad things must come to________end, ________ terrible an experience is. A．the; whatever B．an; however C．/; how D．a; what 6．—Did you return Fred’s call? —I didn’t need to ____ I’ll see him tomorrow. A．though B．unless C．when D．because 7．I will try my best to get lo the station ahead of time ____ I have to walk all the way there. A．so that B．as though C．even if D．in case 8．Believe it or not, some English idioms are very difficult to understand ______ you know the meaning of each word. A．as if B．in case C．now that D．even if 9．Just underwater grass floats on the surface if it loses its roots, a nation is lost without its memories. A．since B．while C．as D．when 10．Do not make complaints about being left out___you shy away from sharing your joys and sorrow with others. A．when B．unless C．once D．until 11．I was so proud _______ my team won the ice hockey competition. It made me feel like I could achieve anything. A．while B．when C．before D．until 12．- Have you known each other for long? - Not really. ________ we started to work in this school. A．Just after B．Just when C．Ever since D．Just before 13．_____I had more money, I could buy a car. A．Only if B．If ever C．If only D．Even if 14．The secretary made a note of it _____ she should forget. A．in order that B．in case C．so that D．ever when
高考英语语法专题——状语从句 1. 状语从句的类型 1) 时间状语从句：常见引导词有： when：表示主句和从句的动作同时或先后发生，强调点，表“就在那时；突然”。 while：常表示延续性动词或状态；while也可表示对比的转折。 as soon as：表示从句的动作一发生，主句的动作马上就发生。 hardly / scarcely … when；no sooner … than：表示“还没来得及……就；刚……就”。 directly, immediately, instantly：副词当连词用，表示“一……就”。 the moment, the mi nute, the second：充当连词，等于when / as soon as。 each time, every time, ne xt time, by the time等：也可以引导时间状语从句。 since：引导的时间状语从句，主句常用现在完成时，从句常用一般过去时。常用句型：It is + 段时间+ since从句，“自从……有多长时间了”。 until：常与not连用，表示“直到……才……”；Not until置于句首时，主句要部分倒装；在It is / was…that / who…强调结构中，须连在一起。 2) 让步状语从句：常见引导词有：although, though, even if, even though, as等。 3) 原因状语从句：常见引导词有： because：常用于回答why, 语气最强；强调原因，常与just, only等起强调作用的副词连用；可引导表语从句。 for：是个并列连词，一般不放在句首，常表示一种推测或解释，或用作附加说明，语气弱。 as, since：常译为“既然、由于”，表示十分明显的原因，语气较弱。 now that：表示“既然”的意思。 4) 地点状语从句：常见引导词有：where, wherever等。 5) 目的状语从句：常见引导词有：that, so that, in order that等。目的状语从句的谓语动词 常与情态动词连用，否则可能是结果状语从句。不可置于句首。目的 状语从句还可以用动词不定式来替换。 6) 结果状语从句：常见引导词有：that, so that, so … that, such … that …等。 7) 方式状语从句：由as, as if(though)等引导。 8) 比较状语从句：由than, as等引导。 9) 条件状语从句：由if, unless, so (as) long as, in case, once, a far as, on condition that等引 导。 2.注意： 1) 主将从现规则：在时间状语从句、条件状语从句、让步状语从句、方式状语从句中， 若主句用一般将来时，或是祈使句，或是含有情态动词的谓语形式，从句则用一般现在时表示将来时，如：You can join our club when you get a bit older. 2) 疑问词+ ever和no matter + 疑问词的区别：疑问词+ ever可引导名词性从句和让步 状语从句；no matter + 疑问词，只能引导让步状语从句。
专题十一状语从句 状语从句在高考试题中由于其他从句的干扰，以及倒装句，强调句的介入，使得状语从句更为复杂。状语从句是一种副词性从句，通常由一个从属连词或一个起连词作用的词组引导。状语从句 1. 时间状语从句 常见的连词(组)： when, while, as, before, after, once, till, until, as soon as, now that, hardly ...when, scarcely ...when, no sooner ...than等。 可以引导时间状语从句的副（介）词（短语）或名词短语： directly, instantly, immediately, by the time, the moment, the second, the minute, the instant, every time, each time, next time, the last time等。 注意点如下： (1) when, while, as引导的时间状语从句 as表示“当……的时候”，往往和when/ while通用，但它着重强调主句与从句的动作或事情同时或几乎同时发生。when(at or during the time)既可以表示在某一点的时候，又可以表示在某一段时间内，主句与从句的动作或事情可以同时发生也可以先后发生。while强调一段时间，仅表示从句和主句的动作同时发生，并且有延续意义，该从句中的动词一般要用延续性动词，从句中常用过去进行时态或一般过去时态；当when表示a period of time时，两者可以互换。 She came up as I was cooking.(同时) 在我做饭时，她走了过来。 When we were at school, we went to the library every day.(在一段时间内) 当我们在学校时，每天都去图书馆。 While they were watching TV, I was preparing myself for the coming examination. 他们在看电视，而我在为即将到来的考试做准备。 Strike while the iron is hot. 趁热打铁。( 不可用as或when，这里的while意思是“趁……”) (2) before引导状语从句时的常见重点句型 ①It will (not) be ...before ... 还要……才，要不了多久就…… It was (not) ...before ... 过了……才(没多久就……) It was a long time before I got to sleep. 过了好长时间我才睡着了。 It wasn t long before he told me about the news. 没多久他就告诉了我那条新闻。 ②不等……就……；在……之前就…… The telephone rang off before I could answer it. 我还没来得及接电话，电话就挂断了。 ③刚……就…… He hardly entered the room before he heard the telephone ring. 他刚进屋电话铃就响了。
高考英语新状语从句知识点真题汇编含答案解析(2) 一、选择题 1．––Why does Jack Ma still work so hard he has already owned so much money? –– Maybe he pursues more than money. A．while B．as C．when D．before 2．______the damage is done, it will take many years for the farmland to recover. A．Until B．Unless C．Once D．Although 3．There are other languages that sound extremely different, ________ they’re conveying exactly the same meaning. A．as though B．even though C．so that D．in that 4．The basic model function of the hero seems to remain constant, ______ the precise qualities of hero may vary over time. A．in case B．as if C．so that D．even though 5．Believe it or not, some English idioms are very difficult to understand ______ you know the meaning of each word. A．as if B．in case C．now that D．even if 6．Just underwater grass floats on the surface if it loses its roots, a nation is lost without its memories. A．since B．while C．as D．when 7．House prices vary from place to place and are usually high ______ there are famous schools. A．where B．when C．which D．whether 8．The leaders of Catalonia said that he had decided to delay the declaration of independence ______ they could have a further negotiation with Spanish government. A．in case B．in order to C．so that D．not until 9．Under the regulation, restaurants and hotels shall stop offering throwaway items_______customers request them. A．since B．once C．unless D．until 10．_____ you feel that your friend is mean at times, cherishing your friendship is a normal part of life. A．Even though B．Now that C．As though D．In case 11．These masterpieces in the Louvre Museum reach out to us across the centuries ______ time itself were nothing. A．even if B．even though C．as though D．only if 12．—We have decided to go for a picnic tomorrow, Jack. Are you going with us? —Well, ______ you are going, so will I. A．when B．since C．if D．while 13．____ I look back to those days as a child, I really hope to spare more time to accompany my father.
高考英语专题状语从句知识点真题汇编及解析 一、选择题 1．Tom was so angry____ he heard his friend betrayed him____ he tore the letter into two immediately. A．that; when B．that; that C．when; what D．when; that 2．______ the environmental impacts of larger plastics are well documented, very little is understood about the dangers associated with micro plastics. A．While B．As C．Because D．If 3．Manchester United has decided that Wayne Rooney will not be sold to any other club no matter how much money is offered or ______ the potential risks of keeping an unhappy player. A．however B．whether C．what D．whatever 4．I will try my best to get lo the station ahead of time ____ I have to walk all the way there. A．so that B．as though C．even if D．in case 5．_____ I once made some mistakes, I won’t spend a moment of the future regretting what might have been. A．Until B．While C．Unless D．Because 6．Believe it or not, some English idioms are very difficult to understand ______ you know the meaning of each word. A．as if B．in case C．now that D．even if 7．House prices vary from place to place and are usually high ______ there are famous schools. A．where B．when C．which D．whether 8．The leaders of Catalonia said that he had decided to delay the declaration of independence ______ they could have a further negotiation with Spanish government. A．in case B．in order to C．so that D．not until 9．I was so proud _______ my team won the ice hockey competition. It made me feel like I could achieve anything. A．while B．when C．before D．until 10．_____ you may meet, you should face the challenge bravely. A．However a serious problem B．What a serious problem C．However serious a problem D．What serious a problem 11．Many countries have a Mother’s Day, ________ they don't always fall on the second Sunday in May. A．when B．though C．as D．once 12．—We have decided to go for a picnic tomorrow, Jack. Are you going with us? —Well, ______ you are going, so will I. A．when B．since C．if D．while 13．Peter had been puzzled over the problem for over an hour___________ all at once the solution flashed across his mind. A．when B．while C．then D．as 14．Elephants usually won’t attack a person ________ one becomes a danger to them. A．until B．although C．unless D．when
高考英语语法状语从句习题及讲解 1. 状语从句的类型 1〕时间状语从句：常见引导词有： when：表示主句和从句的动作同时或先后发生，强调点，表“就在那时；突然”. while：常表示延续性动词或状态；while也可表示对比的转折. as soon as：表示从句的动作一发生，主句的动作马上就发生. hardly / scarcely … when；no sooner … than：表示“还没来得及……就；刚……就”. directly, immediately, instantly：副词当连词用，表示“一……就”. the moment, the minute, the second：充当连词，等于when / as soon as. each time, every time, next time, by the time等：也可以引导时间状语从句. since：引导的时间状语从句，主句常用现在完成时，从句常用一般过去时.常用句型：It is + 段时间+ since从句，“自从……有多长时间了”. until：常与not连用，表示“直到……才……”；Not until置于句首时，主句要部分倒装；在It is / was…that / who…强调结构中，须连在一起. 2〕让步状语从句：常见引导词有：although, though, even if, even though, as等. 3〕原因状语从句：常见引导词有： because：常用于回答why, 语气最强；强调原因，常与just, only等起强调作用的副词连用；可引导表语从句. for：是个并列连词，一般不放在句首，常表示一种推测或解释，或用作附加说明，语气弱. as, since：常译为“既然、由于”，表示十分明显的原因，语气较弱. now that：表示“既然”的意思. 4〕地点状语从句：常见引导词有：where, wherever等. 5〕目的状语从句：常见引导词有：that, so that, in order that等.目的状语从句的谓语动词常与情态动词连用，否则可能是结果状语从句.不可 置于句首.目的状语从句还可以用动词不定式来替换. 6〕结果状语从句：常见引导词有：that, so that, so … that, such … that …等. 7〕方式状语从句：由as, as if〔though〕等引导.
状语从句 一．分类： such+n.+that（如果……以致）that（所以，因此）
让步状语从句：though/although不可同but连用。 though/although （虽然）however （可是）even though/if（即使） no matter+what/which/where/who/when =whatever/whichever/wherever/whoever/whenever （不论什么/哪一个/哪里/谁/何时） 比较状语从句：as （正如）as…as（和……一样）not as/so … as （不如……）than（比……更）the+比较级…+the+比较级（越……越……） 条件状语从句：if（假设）unless（如果不）so long as（只要）on condition that （如果） * 方式状语从句：as（像……那样地）just as（正像）as if（好像）as though（好像） 二．各种状语从句的简化方法： 1 作状语。 】 例：After she sang，she left the rich man's house．= After singing，she left the rich man's house．2．以as soon as引导的状语从句的主语若与主句主语一致时，从句等于on+doing sth.,作状语，此时的动词为非延续性动词。 例：Mary began to operate on the wounded soldiers as soon as he arrived at the village． = Mary began to operate on the wounded soldiers on arriving at the village． 3．时间状语从句和条件状语从句的主语和主句主语一致时，有时可简化为不定式作状语。 例：She stopped when she saw her husband．= She stopped to see her husband．If you want to understand the farmers，you must go to the countryside． = To understand the farmers，you must go to the countryside． 4．结果状语从句和目的状语从句的主语与主句主语一致时，可以简化为不定式作状语；若两者主语不一致时，则应简化为不定式的复合结构作状语。 例：He was so tired that he couldn't go any further．= He was too tired to go any further． I came here so that I could ask some questions．= I came here(in order) to ask some questions．5．以when，while引导的时间状语从句和以if引导的条件状语从句的主语若与主句主语一致时，从句等于when/while/if +doing sth.作状语，表示谓语动作发生在该状语动作的进行过程之中。 。 例：When he turned on the radio，he found it broken．= When turning on the radio，he found it broken．While she was walking along the street，she was hit by a car．= While walking along the street，she was hit by a car． 6．原因状语从句的主语与主句主语一致时，可简化为分词短语作状语。 例：Since l didn't know Chinese，I tried to speak to her in English．= Not knowing Chinese，I tried to speak to her in English． 注意：形容词短语也可作表示原因的状语，来代替原因状语从句，放在句首、句末均可，但一般应加逗号。 例：As he was thirsty and eager to get a little rest，he went into the tea-house． = Thirsty and eager to get a little rest，he went into the tea-house．
高考英语状语从句知识点真题汇编及答案(1) 一、选择题 1．____ I look back to those days as a child, I really hope to spare more time to accompany my father. A．However B．Whenever C．Whatever D．Wherever 2．Why do many students stick to private tutoring _____ they could easily master such knowledge at school? A．unless B．before C．after D．when 3．______the damage is done, it will take many years for the farmland to recover. A．Until B．Unless C．Once D．Although 4．A Chinese company has created a new facial recognition system that can identify people ______ they are wearing masks. A．provided that B．in case C．as though D．even if 5．He differed _________ other people __________ he always looked further ahead in his work. A．from; in which B．from; in that C．with; in which D．with; in that 6．The basic model function of the hero seems to remain constant, ______ the precise qualities of hero may vary over time. A．in case B．as if C．so that D．even though 7．_____ I once made some mistakes, I won’t spend a moment of the future regretting what might have been. A．Until B．While C．Unless D．Because 8．House prices vary from place to place and are usually high ______ there are famous schools. A．where B．when C．which D．whether 9．The leaders of Catalonia said that he had decided to delay the declaration of independence ______ they could have a further negotiation with Spanish government. A．in case B．in order to C．so that D．not until 10．—Mr. Robert, I’d like to take a gap year to volunteer for a global anti-Aids campaign.—That’s great, ______ you can afford the time. A．provided that B．in case C．even if D．so that 11．I was so proud _______ my team won the ice hockey competition. It made me feel like I could achieve anything. A．while B．when C．before D．until 12．He hasn’t got any hobbies，________you call watching TV a hobby. A．when B．if C．unless D．since 13．Under the regulation, restaurants and hotels shall stop offering throwaway items_______customers request them. A．since B．once C．unless D．until
状语从句高考考点高考状语从句讲解 语法专题 状语从句 考点归纳 考点一：对when，while，as，since等词的辨析 when，while，as，since在引导时间状语从句时的区别可参见下表： 和从句动词所表示的动作或状态是同时发生的，它引导的从句用延续性动词，若从句中是非延续性动词，不能用while。 表示“一边……一边”的意思时用as或while。 As/While she was cooking she was singing songs、 She sang as she cooked、 当主句谓语动词表示短暂动作，而从句动作可以持续一段时间时，三个连词都可以用。 Tom poke his leg while/when/as he was playing football、注意： ① when也可用作并列连词，其意义为“就在那时，这时”，相当于and at this/that time，常用下列句式中： We were having a meeting when someone poke in、 We were about to set off on our way，when it suddenly began to rain、
He had just left the room when it rained、 另外when还可表示原因“既然”。 It was foolish of you to take a taxi when you could easily walk there in five minutes、 ②while除引导时间状语从句外，还可引导让步或条件状语从句及作并列连词连结两个并列的简单句。如：While he was respected，he was not liked、 There will be life while there is water and air、 He is a worker while I am a doctor、 since引导从句时在主句是现在完成时的条件下，从句若为非延续性动词的一般过去时，表示从该动作的完成时刻算起，因此动词的语法形式与词义一致，是肯定意义；若从句动词为延续性动词的一般过去时，表示动作或状态从最后一次发生到现在。因此其含义与动词的词义恰好相反，具有否定意义，若从句延续性动词用现在完成时，则动词的语法形式与词义一致，是肯定意义。 I haven”t heard from her since she left Beijing、 自从她离开北京后，我从未收到她的信。 I haven”t written to her since she lived in London、 自从她离开伦敦以后，我从未给她写信。 Since I have been at this school we have three headmasters、