英语状语从句的用法（I）
定义与用法：
在复合句中修饰主句或主句中的某一谓语成分的从句叫状语从句。状语从句通常由从属连词或起连词作用的词组引导。状语从句可放在主句之前或之后，放在主句之前时一般用逗号与主句分开。有时可置于主句中间，前后用逗号。状语从句根据它表达的意思不同，可分为时间、地点、原因、目的、结果、条件、方式、比较、让步等九类。
一、时间状语从句
时间状语从句是表示时间关系的从句。可以引导时间状语从句的连词很多，根据意义和主从句之间的时间关系，通常可分为以下几种情况：
A．when, while, as, whenever。
when, while, as表示主句谓语作和从句的谓语动作同时发生或几乎同时发生。分述如下：
1．when
①when (at or during the time that ) 既可以表示在某一点的时候，又可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。表示点时间时，从句中用短暂性动词；表示段时间时，用持续性动词。 I home, my family were already having dinner.我到家的时候，全家已在吃晚饭。（when表示点时间）
laughing,.当他们还在说笑的时候，老师进来了。（when表示段时间）
【考例】Don’t be afraid of asking for help ____it is needed. ( NMET2003单项填空)
A. unless B. since C. although D. when
【思路点拨】答案为D此题考查when用作连接词用来引导时间状语从句。
提示：① 注意：当when引导时间状语从句时，从句中应用一般现在时代替一般将来时（主“将”从“现”）。
【考例】
---When _____again?
--- When he____, I will let you know. (1988年全国卷)
A. he comes, comes
B. will he come, will come
C. he comes, will come
D. will he come, comes
②当when引导时间状语从句时，状语从句的主语可以省略。
【考例】Michael used to look hurt and surprised when ________.
A) scolding B) to scold
C) having scolded D) scolded
③注意：when可以表示“正当…时候突然…”（= and at that moment/and suddenly then），这样使用的when只能跟在前一分句之后，此时的when常视作并列连词。常用于下列句式：
Somebody was doing something when…/
Somebody was about to do something when… / Somebody had just done something when…
这里when表示一种原来没有预料到的新情况出现。又是这一新情况打断了主句表示的正在进行的活动，或制止了即将发生的情况。在这种情况下，前面的分句常用进行式、完成式或
They the World suddenly the lights went out.他们正看着世界杯比赛，突然灯灭了。 他正要上床，忽然门铃响了。 他们刚到家，天就开始下雨了。
[考例1] He was about to tell me the secret ____ someone patted him on the shoulder. (2002上海高考题)
A. as B. until C. while D. when
[考例2] I had just started back for the house to change my clothes ______ I heard voices.
A) as B) when C) after D) whole
2．while
① while意思是“当„„的时候”或“在某一段时间里”。while通常表示一段时间，主句中的动作或事情在从句中的动作或事情的进展过程中发生，从句中宜用持续性动词作谓语。在when表示a period of time
时，while和when两者可以互换。 她在看报的时候睡着了。（这里的while可换成when） 趁热打铁。(用as或when不可，这里的while意思是“趁着„„（的一段时间里）”)
提示：虽然during 与 while 意思很相近，但是during是介词，不能引导从句。
② while有时可以作并列连词，表示对比，可译成“……而……”，此时的while只能跟在前一分句之后。 我喜欢英语而他却喜欢数学。 我们睡觉而上尉担任警戒。
③ while有时可引导让步状语从句，意思是“虽然”，等于although，此时的while引导的从句常放在句首。 they love their children, they are strict with them.虽然他们都爱他们的孩子，但却对他们要求严格。
[考例] _____ I really don’t like art, I find his work impressive. [2007 山东卷]
A．As B．Since C．If D．While
3．as
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。但它还有一些特定的意义：
① as表示点时间时，从句中用短暂性动词；表示段
时间时，从句中用延续性动词。as和when两者经常可以通用。
The thief was caught as/ when he was stealing in the supermarket.小偷在超市行窃时被逮住了。（段时间） I saw Jim as/ when he left the meeting room.吉姆离开会议室时候我看到了他。（点时间）
② as表示 “一边……一边……”，强调从句和主句中两个动作交替进行或同步进行。
They talked as they walked.他们边走边聊。
He looked behind from time to time as he went.他一边走，一边不时地往后看。
③ as表示“随着”。
As time goes on, it's getting warmer and warmer.随着时间的推移，天气变得越来越暖了。
4．when, while, as的用法区别：
简言之：
◆ while表时间，从句需用延续性动词，切不可用瞬间动词。
◆ when表时间，从句既可以用延续性动词，又可以用瞬间动词。
◆ as表时间，与when相似，但侧重强调主从句动作同点或同段进行。
◆ when, while后可以接分词短语。
注意：在下列情况下，三者之间不能完全替换使用：
(1) 只有as, when 可以引导短暂性动作的动词。 Just as / Just when / When I stopped my car, a man
came up to me. 当我停车时，一个男子向我走来。 注意：as更强调同一时间或紧接的一前一后或伴随着的变化。
We listened to the singer sing as he played the guitar.我们听着歌星边弹吉它边演唱。（一边„一边同时） I thought of it just as you opened your mouth.你一张嘴我就知道你要说什幺。（紧接着一前一后的动作） As he grew older, he became less and less active.随着他年龄的增长，他变得越来越不活泼了。（伴随的变化）
(2) when更强调特定时间，还可表示从句中的动作先于或后于主句的动作。
He transplanted the little tree to the garden________ it was the best time for it.(2005, 上海卷)
A. where B. when C that D. until (这里强调特定时间)
注意：当从句的动作发生于主句动作之前，只能用when 引导这个从句，不可用as 或 while。
When I had given Mary the spare ticket, I found my own already gone.当我把多余的票给了玛丽时，我才发现我自己的票已不知去向。（从句动作发生在主句之前，注意主从句的时态）
When I finally got there, he meeting had been on for ten minutes.当我最终赶到那里时，会议已开始十分钟了。（从句动作发生在主句之后）
(3) while引导的从句的谓语动词动作必须是持续的，
侧重主句动作和从句动作相对比，同时while引导的从句一般用进行时。如：
Please do not talk so loud while others are working.
[考例]The cost of living in Glasgow is among the lowest in Britain, the quality of life is probably one of the highest. （2006年天津卷）
A. since B. when C. as D. while
4．Whenever
whenever“无论何时”是when的强势语，它描述的不是一次性动作，而是经常发生的习惯性动作，类似的表达还有each time…/ every time…等。
You are always welcome whenever you come.无论你何时来都欢迎。
Whenever(Every time/ Each time) we met with difficulties, they came to help us.
每当我们遇上困难的时候，他们就来帮我们。
[考例]You can eat food free in my restaurant _______ you like.（2004, 重庆卷）
A. whenever B. wherever
C. whatever D. however
5. as soon as, immediately, directly, the moment, the minute, no sooner … than …, hardly/ scarcely… when… 表示“一„就„”的结构
这些从属连词或副词引导的从句都表示从句的动作一发生，主句的动作随即发生，常译为“一„„就„„”。从句中用一般时态代替将来时态。分述如
下：
1、as soon as 是最普通的表示“一„就„”的结构。注意：尽管动作有先后，但由于衔接紧密，as soon as从句和主句可以使用相同的时态。 我一赶到家天就开始下雨。
2、immediately, directly看起来是副词，但这里把它当连词用，等于as soon as。
3、the moment, the minute, the instant, the second这几个名词短语也可用作连词，直接引导时间状语从句，表示“一„就„”。
He said he'd turn on TV the moment he got home. 他说他一到家就打开电视机。
Tell him I need to see him the minute he arrives. 告诉他，他一到我就要见他。
The second the bell rang, the students rushed out of the classroom.铃一响，学生就冲出了教室。
[考例]
— Did you remember to give Mary the money you
owed her? （2001, 北京春）
— Yes. I gave it to her _______ I saw her.
A. while B. the moment
C. suddenly D. once
（2002年高考短文改错）… I was so tired that I fell
asleep at the moment my head touched the pillow．
4、hardly/ scarcely…when…; no sooner … than …表示
这两个连词词组都是表示主句与从句动作随即发生，意为“一„就“。主句动词用过去完成时。要注意no sooner„ than„, hardly/scarcely„when„这一结构的时态搭配：no sooner与hardly/scarcely引导的主句谓语动词应用过去完成时，而than与when的从句中谓语应用一般过去时，此外，当把no sooner和hardly/scarcely提到句首时，应用倒装语序。例：
I had hardly / scarcely got home when it began to rain.我一赶到家天就开始下雨。
I had no sooner got home than it began to rain. 我一赶到家天就开始下雨。
Hardly / Scarcely had I got home when it began to rain.
No sooner had I got home than it began to rain.
[考例] --- Did Linda see the traffic accident?
--- No, no sooner ______ than it happened. （2006年天津卷）
A. had she gone B. she had gone
C. has she gone D. she has gone
7. till, until和not„until
[考例] It is difficult for us to learn a lesson in life ______ we've actually had that lesson. (07天津卷)
A. until B. after C. since D. when
此两个连词意义相同。肯定形式表示的意思是
1) 肯定句：主句谓语动词必需是延续性动词，主句从句都为肯定式，意为“某动作一直延续到某时间才停止”。
He remained there until she arrived.
他一直留到她来。
You may stay here until the rain stops.
你在这里呆到雨停。
[考例]A good storyteller must be able to hold his listeners’ curiosity _____ he reaches the end of the story.（2003, 上海卷）
A. when B. unless C. after D. until
2) 否定句：主句谓语动词可以是非延续性动词，从句是肯定式，意为“某动作直到某时间才开始”。如： She didn't arrive until 6 o'clock. 她直到6点才到。 Don't get off the bus until it has stopped. 公共汽车停稳后再下车。
[考例]My uncle _______ until he was forty-five.（2000，上海卷）
A. married B. didn’t marry
C. was not marrying D. would marry
3)till不可以放在句首，而until可以放在句首。如： Until you told me, I had heard nothing of what happened. 直到你告诉我，我才知道出了什么事。
【考例研究】
1. Peter was so excited _______he received an invitation from his friend to visit Chongqing. （2009重庆卷） A. where B. that C. why D. when
【解析】考查连词用法。此处句意为当他收到来自于他朋友邀请他去参观重庆的邀请时，他非常兴奋，故选D, 为时间状语从句，有句意可防止误选B.
2．She had just finished her homework ____ her mother asked her to practice playing the piano yesterday. （2009福建卷）
A. when B. while C. after D. since
【解析】考查状语从句。根据主从句的动词时态可知主句谓语动词的动作在从句谓语动词之前已经完成，引导词的意思是：当……的时候。【答案】A
3. – I wonder how much you charge for your services. -- The first two are free ____ the third costs $30.（2009安徽卷）
A. while B. until C. when D. before
【解析】这里起转折作用,while表示”但是”,可接句子.”前两个免费,但第三个要收费30元” 【答案】A
4. It just isn’t fair; _____ I was working as a waiter last month, my friends were lying on the beach. （2009辽宁卷）
A whenever B. though C. for D. while
【解析】考查连词辨析。按照句意I和my ffiends前后对比，though虽然，但是仅有转折没有对比之意，while 意思是“然而，当---时，”既有转折，又有对比之意，符合句意.【答案】D