涉及状语从句的几种特定时态1. “主将从现”原则即若主句为一般将来时，时间和条件状语从句通常要用一般现在时表示将来，而不能直接使用将来时态。
如：I’ll give her the telex when she comes. 她来时把电传交给她。
I’ll return the book as soon as I have read it. 这书一看完我就送还。
He’ll have four years at university after he leaves school. 他中学毕业后要上四年大学。
2. since与完成时since 引导时间状语从句时，其主句通常要用现在完成时，有时也用现在完成进行时。
如：She has had another baby since I saw her last. 从上次我见到她以来，她又生了一个孩子。
He has grown an inch since I saw him. 我上次见到他以后他已长高了一英寸。
注：当主句为“It + be + 一段时间”时，则通常用一般现在时代替现在完成时。
如：It’s more than three years now since I saw her last. 我们已有三年多没见面了。
3. 特定句式的时态由no sooner. . . than, hardly [scarcely]…when引出的时间状语从句，其主句通常用过去完成时，从句通常用一般过去时。
如：Hardly had he arrived when she started complaining. 他刚到她就抱怨起来。
No sooner had he gone to sleep than the telephone rang. 他刚睡着电话铃就响了。
We had no sooner set out than a thunderstorm broke. 我们刚出发就下起一阵雷暴。
No sooner had she agreed to marry him than she started to have terrible doubts. 她刚同意嫁给他她就开始产生可怕的疑虑。
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”。
例如：I will call you as soon as I arrive in Beijing. 我一到北京就给你打电话。
（这是由as soon as引导的时间状语从句，从句中的谓语动词arrive是一般现在时，表示一般将来时，决不可用will arrive）As soon as I have finished this work, I will go home. 我一完成此工作，就回家。
（从句中的谓语动词用现在完成时have finished，表示将来完成时,决不可用will have finished）If he comes back, please let me know.如果他回来了，请通知我。
（从句中的谓语动词用comes back,表示一般将来时，决不可用will come back）状语从句讲解和练习状语修饰动词、形容词、副词或整个句子。
通常由副词、介词短语、动词不定式、分词和从句等担当。
例如：1. Naturally , our grandparents were pleased to get our phone call .(副词)2. We worked hard , from sunrise to sunset . (介词状短语)3. To help my disabled aunt , I spend an hour working in her houseevery day . (不定式)4. Seen from a distance , the farmhouse looked deserted . (过去分词)5. I know how to light a camp fire because I had done it before .（原因状语从句）状语的位置比较灵活，可以位于句首、句末或句中。
enough用作状语修饰形容词和副词时必须后置。
状语从句主要用来修饰主句或主句的谓语。
一般可分为九大类，分别表示时间、地点、原因、目的、结果、条件、让步、比较和方式。
尽管种类较多，但由于状语从句与汉语结构和用法相似，所以理解和掌握它并不难。
状语从句的关键是要掌握引导不同状语从句的常用连接词和特殊的连接词即考点。
现分别列举如下: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 … whenI 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 sawthe guard.No sooner had I arrived home than it began to rain.Every time I listen to your advice, I get into trouble.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.3．原因状语从句常用引导词：because, since, as, for特殊引导词：seeing that, now that, in that, considering that, giventhat.My friends dislike me because I’m handsome and successful.Now that everybody has come, let’s begin our c onference. The higher income tax is harmful in that it may discourage peoplefrom trying to earn more.Considering that he is no more than 12 years old, his height of1.80 m is quite remarkable.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 thatThe boss asked the secretary to hurry up with the letters so thathe 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, so… that, such … that,特殊引导词：such that, to the degree that, to the extent that, tosuch a degree that,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 an 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 thatWe’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 meetinghere.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, whicheverMuch as I respect him, I can’t agree to his proposal.尽管我很尊敬他，我却不同意他的建议。
The old man always enjoys swimming even though the weather isrough.No matter how hard he tried, she could not change her mind.He won’t listen whatever you may say.8．比较状语从句常用引导词：as(同级比较), than(不同程度的比较)特殊引导词：the more … the more … ; just as …，so…; A is to B what /as X is to Y; no … more than; not A so much as BShe is as bad-tempered as her mother.The house is three times as big as ours.The more you exercise, the healthier you will be.Food is to men what oil is to machine. 食物之于人，犹如油之于机器。
