状语从句
(发布时间: 2008-5-20 16:20:00 来自:环球外语在线)
 
状语从句
1 地点状语从句
  地点状语从句通常由where, wherever 引导。例如:
  Where I live there are plenty of trees. 我住的地方树很多。
  Wherever I am I will be thinking of you. 不管我在哪里我都会想到你。
 
2 方式状语从句
  方式状语从句通常由as, (just) as…so…, as if, as though引导。
1)  as, (just) as…so…引导的方式状语从句通常位于主句后,但在(just) as…so…结构中位于句首,这时as从句带有比喻的含义,意思是"正如…","就像",多用于正式文体。
Always do to the others as you would be done by. 你希望人家怎样待你,你就要怎样待人。
  As water is to fish, so air is to man. 我们离不开空气,犹如鱼儿离不开水。
 Just as we sweep our rooms, so we should sweep backward ideas from our minds.
   正如打扫房屋一样,我们也要扫除我们头脑中落后的东西。
2)as if, as though
   两者的意义和用法相同,引出的状语从句谓语多用虚拟语气,表示与事实相反,有时也用陈述语气,表示所说情况是事实或实现的可能性较大。汉译常作"仿佛……似的","好像……似的"。例如:
   They completely ignore these facts as if (as though) they never existed. 他们完全忽略了这些事实,就仿佛它不存在似的。(与事实相反,谓语用虚拟语气。)
  He looks as if (as though) he had been hit by lighting. 他那样子就像被雷击了似的。(与事实相反,谓语用虚拟语气。)
   It looks as if the weather may pick up very soon. 看来天气很快就会好起来。(实现的可能性较大,谓语用陈述语气。)
   说明:as if / as though也可以引导一个分词短语、不定式短语或无动词短语。例如:
   He stared at me as if seeing me for first time. 他目不转睛地看着我,就像第一次看见我似的。
 He cleared his throat as if to say something. 他清了清嗓子,像要说什么似的。
 
3 原因状语从句
比较because, since, as和for:
1)because语势最强,用来说明人所不知的原因,回答why提出的问题。当原因是显而易见的或已为人们所知,就用as或 since。例如:
   I didn't go, because I was afraid. 我不去是因为我怕。
   Since /As the weather is so bad, we have to delay our journey. 天气那么糟,旅行推迟了。
2)由because引导的从句如果放在句末,且前面有逗号,则可以用for来代替。但如果不是说明直接原因,而是多种情况加以推断,就只能用for。例如:
   He is absent today, because / for he is ill. 他今天缺席,因为他病了。
   He must be ill, for he is absent today. 他一定病了,所以今天缺席。
4 目的状语从句
  表示目的状语的从句可以由that, so that, in order that, lest, for fear that, in case等词引导。例如:
  You must speak louder so that /in order that you can be heard by all. 你必须大点声,别人就能听见了。
  He wrote the name down for fear that(lest) he should forget it. 他写下了这个名字以免以后忘记。
  Better take more clothes in case the weather is cold. 最好多穿点衣服,以防天发冷。
  
5 结果状语从句
 结果状语从句常由so…that 或 such…that引导。so…that与such…that之间可以转换。例如:
    The boy is so young that he can't go to school. 这男孩年龄太小,不能上学。
     He is such a young boy that he can't go to school
 
6 条件状语从句
   连接词主要有 if, unless, as/so long as, on condition that 等。if 引导的条件句有真实条件句和非真实条件句两种。非真实条件句将在虚拟语气中阐述。
   unless = if not.  例如:
   Let's go out for a walk unless you are too tired. 如果不太累,我们去散散步。
   If you are not too tied, let's go out for a walk.
典型例题
You will be late ___ you leave immediately. 
A. unless  B. until  C. if  D. or
   答案A。句意:除非你立即走,否则你就回迟到的。可转化为 If you dong leave immediately, you will be late。B、D句意不对,or表转折,句子如为 You leave immediately or you will be late. 
 
7 让步状语从句
1)though, although引导的让步状语从句,后面的从句不能有but,但是 though 和yet可连用。例如:
Although it's raining, they are still working in the field. 虽然在下雨,但他们仍在地里干活。
    He is very old, but he still works very hard. 虽然他很老了,但仍然努力地工作。
2)  as, though 引导的让步从句必须表语或状语提前(形容词、副词、分词、实义动词提前)。例如:
虽然是个小孩,该做什么不做什么,他全知道。
3)  ever if, even though 即使。例如:
We'll make a trip even though the weather is bad. 即使天气不好,我们也要去远足。
4)  whether…or… 不管……都。例如:
    Whether you believe it or not, it is true. 信不信由你,这确实是真的。
5) "no matter +疑问词" 或"疑问词+后缀ever" 。例如:
No matter what happened, he would not mind. =Whatever happened, he would not mind. 不管发生什么,他不在意。
   替换:no matter what = whatever
        no matter who = whoever
        no matter when = whenever
        no matter where = wherever
        no matter which = whichever
        no matter how = however
 
注意:no matter 不能引导主语从句和宾语从句。
   (错)No matter what you say is of no use now.
   (对)Whatever you say is of no use now. 你现在说什么也没用了。(Whatever you say是主语从句)
  (错)Prisoners have to eat no matter what they're given,
   (对)Prisoners have to eat whatever they're given.囚犯们只能给什么吃什么。
 
8 比较while, when, as
1)as, when 引导短暂性动作的动词。例如:
我一刹车,有一个人向我走来。
2)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。这就是它们的区别之一。
 干完活后,你可以休息一下。(连接的两个动作有时间间隔)
3)从句表示"随时间推移"连词能用as,不用when 或while。例如:
    As the day went on, the weather got worse. 日子一天天过去,天气越变越坏。
   
9 比较until和till
牛刀小试
我一直睡到半夜时醒了。
I slept until midnight.
公共汽车停稳后再下车。
Don't get off the bus until it has stopped.
直到你教我后,我才会做。
I didn't manage to do it until you had explained how.
此两个连词意义相同。肯定形式表示的意思是"做某事直至某时",动词必须是延续性的。否定形式表达的意思是"直至某时才做某事"。动词为延续性或非延续性都可以。正确使用这两个连词的关键之一就在于判断句中的动词该用肯定式还是否定式。肯定句:I slept until midnight. 我一直睡到半夜时醒了。
 
Wait till I call you. 等着我叫你。(在肯定句中可用before代替。)
区别:1)until可用于句首,而till通常不用于句首。例如:
Until you told me, I had heard nothing of what happened.
直到你告诉我以前,出了什么事我一点也不知道。
2)until when 疑问句中,until要放在句首。例如:
---Until when are you staying? 你呆到什么时候?--- Until next Monday.呆到下周一。 
注意:否定句可用另外两种句式表示。
1)Not until…在句首,主句用倒装。例如:
Not until the early years of the 19th century did man know what heat is. 直到19 世纪初,人类才知道热为何物。
Not until I began to work did I realize how much time I had wasted. 直到工作,才认识到我已蹉跎了几多岁月。
2)It is not until… that… 。例如:
It was not until I began to work that I realized how much time I had wasted.
 
10 表示"一…就…"的结构
hardly/scarcely…when/before, no sooner…than 和as soon as都可以表示"一…就…"的意思。例如:
   I had hardly / scarcely got home when it began to rain. 刚回家,就下起雨来了。
   I had no sooner got home than it began to rain.
   As soon as I got home, it began to rain.
   注意:如果hardly, scarcely 或no sooner置于句首,句子必须用倒装结构,否定词在句首。例如:
   Hardly / Scarcely had I got home when it began to rain.
No sooner had I got home than it began to rain.
 
一般现在时
主要用来表示人、事物的现在状况和特点;表示经常或习惯性的动作,句子中常有often, always, from time to time 等时间状语;表示客观规律和永恒真理等。
只要他努力工作,我不介意他什么时候做完试验。
现在进行时
表说话时或目前一段时间内正在进行的活动;与频率副词,如always,constantly,continually,again等连用,表示说话人的某种感情色彩(赞叹、厌烦、埋怨等)。
考点一与时间和条件状语从句中,一般现在时代替一般将来时同理,只是强调进行持续。
考点二---下列动词come, go, arrive, leave, start, begin, return等现在进行时可以表示将来。例如:
  I'm leaving tomorrow. 明天我要走了。
  Are you staying here till next week? 你会在这儿呆到下周吗?
现在完成时
表示动作发生在过去,完成在过去,但强调与现在情况仍有联系,其结果或影响仍存在。现在完成时有一些标志性的时间状语。
一般过去时
表 在过去某个特定时间发生且完成的动作,或过去习惯性动作,不强调对现在的影响,只说明过去。
过去进行时
表示过去某个时间点或某段时间内正在发生的动作。主要用法是描述一件事发生的背景;一个长动作延续的时候,另一个短动作发生。
过去完成时
表示过去某个时间之前已经完成的动作,即过去完成时的动作发生在“过去的过去”,句中有明显的参照动作或时间状语,这种时态从来不孤立使用。
一般将来时
表示在将来某个时间发生的动作或情况。常和tomorrow, next year, in 2008等表示将来的时间状语连用,其表现形式多达5种。
考点一-----主句用一般将来时,从句中一定要用一般现在时替代一般将来时。
考点四-----be to 表示客观安排或受人指示而做某事,be going to 表示主观的打算或计划。
将来进行时
表示将来某个时间正在发生的动作,或按计划一定会发生的事情。
将来完成时
表示在将来某时刻之前业已完成的事情,时间状语非常明显。
 
第5讲I have been here since 1989. I have been here since five months ago.
It is two years since I became a postgraduate student. Great changes have taken place since you left.
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