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状语从句
什么是状语？
状语修饰动词、形容词、副词或整个句子。
1. Naturally, our grandparents were pleased to get our phone call. 2. We worked hard, from sunrise to sunset.
3. To help my disabled aunt, I spend an hour working in her house every day 4. Seen from a distance, the farmhouse looked deserted.
5. I know how to light a camp fire because I had done it before. 状语的位置比较灵活，可以位于句首、句末或句中。
什么是状语从句？
状语从句指句子用作状语时，起副词作用的句子。它可以修饰谓语、非谓语动词、定语、状语或整个句子。状语从句一般由连词(从属连词)引导，也可以由词组引起。 根据其作用状语从句可分为： 1.时间状语从句 2.地点状语从句 3.原因状语从句 4.条件状语从句 5.目的状语从句 6.让步状语从句 7.比较状语从句 8.方式状语从句 9.结果状语从句
状语从句的时态特点
一般情况下，时间和条件状语从句的谓语动词一般用“一般现在时”表示“一般将来时”，用“现在完成时”表示“将来完成时”。
I will call you as soon as I arrive in Beijing.
As soon as I have finished this work, I will go home. If he comes back, please let me know.
1． 时间状语从句
常用引导词：when, as, while, as soon as, before, after, since , till, until 特殊引导词：the minute, the moment, the second, every time, the day，the instant, immediately , directly, no sooner … than, hardly …when, scarcely … when I didn’t realize how special my mother was until I became an adult. While John was watching TV, his wife was cooking.
The children ran away from the orchard(果园), the moment they saw the guard
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No sooner had I arrived home, then it began to rain. Every time I listen to your advice, I get into trouble. 表示“一 ……就……”
除as soon as外，还有三类：
名词型——the moment, the minute, the second, the instant； 副词型——immediately, directly, instantly；
句式型——no sooner…than…, hardly/scarcely…when… The moment I saw him, I fell in love with him.
I came immediately you called. 你一给我打电话，我就马上来。
I had no sooner got home than it began to rain. 我一到家，就开始下雨。 【注意】
如果hardly, scarcely 或no sooner置于句首，句子必须用倒装结构。 Hardly/Scarcely had I got home when it began to rain. No sooner had I got home than it began to rain.
在时间状语从句中，不能用一般将来时、过去将来时态或将来完成时，而要用相应的一般现在时态、一般过去时或现在完成时来代替。
When, while, as(一边...一边...), after, before, as soon as, since, till /until, by the time(到。。。为止, 所在句子的主句应用完成时)
Mozart started writing music when he was four years old. He visited a lot of places while he was traveling.
He left the classroom after he had finished his homework the other day. 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。并且when有时表示“就在那时”, when＝and then; at that moment。 When she came in, I stopped eating.
When I lived in the countryside, I used to carry some water for him.
We were about to leave when he came in.
While引导的从句的谓语动词必须是延续性的，并强调主句和从句的动作同时发生（或者相对应）。并且while有时还可以表示对比。
While my wife was reading the newspaper, I was watching TV. I like playing football while you like playing basketball.
As表示“一边……一边”，as引导的动作是延续性的动作，一般用于主句和从句动作同时发生；as也可以强调“一先一后。 We always sing as we walk.
As we was going out, it began to snow.
before和after引导的时间状语从句
before的本意为“在……之前”，根据具体语境还可理解为“还没来得及/还没有……就……，趁着还没……就……，不知不觉就……，……才……”等。 After表示主句动作发生在从句动作之后。
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It will be four days before they come back.
Einstein almost knocked me down before he saw me. My father had left for Canada just before the letter arrived. They had not been married four months before they were divorced. After you think it over, please let me know what you decide. After we had finished the work, we went home. till或until引导的时间状语从句
till和until一般情况下两者可以互换，但是在强调句型中多用until。
如果主句中的谓语动词是瞬时动词时，必须用否定形式；如果主句中的谓语动词是延续性动词时，用肯定或否定形式都可以，但表达的意思不同。 I didn't go to bed until（till） my father came back.
It was not until the meeting was over that he began to teach me English. I worked until he came back.我工作到他回来为止。 I didn't work until he came back.他回来我这才开始工作。 由since引导的时间状语从句。
since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。一般情况下，从句谓语动词用一般过去时，而主句的谓语动词用现在完成时。但在It is ＋时间＋since从句的句型中，主句多用一般现在时。 I have been in Beijing since you left. Where have you been since I last saw you?
It is four years since my sister lived in Beijing. 我妹妹不在北京住有四年了。 It is five months since our boss was in Beijing.我们老板离开北京有五个月了。
2．地点状语从句
常用引导词：where
特殊引导词：wherever, anywhere, everywhere
Generally, air will be heavily polluted where there are factories. Wherever you go, you should work hard. 句型1：Where＋地点从句，（there）＋主句。
Where there is no rain, farming is difficult or impossible.
They were good persons. Where they went, there they were warmly welcomed. You should have put the book where you found it.
Where the Communist Party of China goes, there the people are liberated. 句型2：Anywhere/ wherever＋地点从句，＋主句。 Wherever the sea is, you will find seamen.
3．原因状语从句
常用引导词：because, since, as, for
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特殊引导词：seeing that(由于，鉴于 ), now that(既然), in that, considering that(考虑到), given that(考虑到).
My friends dislike me because I’m handsome and successful. Now that everybody has come, let’s begin our conference.
Considering that he is no more than 12 years old, his height of 1.80 m is quite remarkable.
Seeing that you’re already at the door, I suppose I must invite you inside. Considering he’s only sixteen year old, he is not fit for the job.
Given that she is interested in children, I am sure teaching is the right career for her. because, since, as, for辨析
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。 I didn’t go, because I was afraid.
Since /As the weather is so bad, we have to delay our journey.
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。 He is absent today, becaus e / for he is ill. He must be ill, for he is absent today. 3) as和for的区别：
通常情况下，as引导的从句在主句前，for引导的从句在主句后。 As the weather is cold, I stay at home.（同义句） I stay at home, for the weather is cold.
4．目的状语从句
常用引导词：so that, in order that
特殊引导词：lest, in case, for fear that，in the hope that, for the purpose that, to the end that
The boss asked the secretary to hurry up with the letters so that he could sign them.The teacher raised his voice on purpose that the students in the back could hear more clearly.
5．结果状语从句
常用引导词：so … that, such … that,
特殊引导词：such that, to the degree that, to the extent that, to such a degree that,
(such 是形容词，修饰名词或名词词组，so 是副词，只能修饰形容词或副词。)
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He got up so early that he caught the first bus. It’s such a good chance that we must not miss it.
To such a degree was he excited that he couldn’t sleep last night.
6．条件状语从句
常用引导词：if, unless,
特殊引导词：as/so long as, only if, providing/provided that, supposing that, in case that, on condition that
We’ll start our project if the president agrees.
You will certainly succeed so long as you keep on trying.
Provided that there is no opposition, we shall hold the meeting here.
条件状语从句和时间状语从句一样，从句的谓语动词不能用一般将来时态、过去将来时态或将来完成时，而要用相应的一般现在时、一般过去时和现在完成时来替代。
Tell me in case you get into difficulty.
Supposing he does not come, shall we go without him?
7．让步状语从句
常用引导词：though, although, even if, even though
特殊引导词： as(用在让步状语从句中必须要倒装)，while ( 一般用在句首 )，no matter …， in spite of the fact that, while, whatever, whoever, wherever, whenever, however, whichever
Much as I respect him, I can’t agree to his proposal.
The old man always enjoys swimming even though the weather is rough.
No matter how hard he tried, she could not change her mind. as, though 引导的倒装句
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）。 Child as /though he was, he knew what was the right thing to do. = Though he was a small child, he knew what was the right thing to do. 注意：
a. 句首名词不能带任何冠词。
b. 句首是实义动词，其他助动词放在主语后。如果实义动词有宾语和状语，随实义动词一起放在主语之前。
Try hard as he will, he never seems able to do the work satisfactorily. = Though he tries hard, he never seems…
no matter who = whoever no matter when = whenever no matter where = wherever no matter which = whichever
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状语从句用法总结完整
