状语从句

Ⅰ状语从句的概念

通常用来说明主句中某一动词．形容词．副词的起状语作用的从句，叫做状语从句。状语从句位置较灵活，可以在主句之前，之后或中间。

　　Ⅱ状语从句的用法

1．时间状语从句

    （1）before 和after引导

    before 引导的从句的动作通常发生在主句动作之后，如果从句是过去时，主句一般要用过去完成时。After引导的从句动作通常发生在主句动作之前，如果主句要用过去时，从句则要用过去完成时。例如：The plane had taken off before he arrived at the airport.

    After he had lived in the south for nearly 20 years, he decided to go to seek his fortune in the north.

    但是如果不强调先后，或是因为从句中使用的是某个状态动词，after和 before句子结构中的谓语动词也可以都用一般过去时。例如：They arrived at the cinema after the film began.

    （2）when, whenever, 和as while引导

     when 表示某个具体的时间，when 可以指一段时间，也可指一点时间，既可表示一时性的动作，又可表示持续的动作。Whenever指的是“任何时间”。 As所表示的动作与主句动作同时发生，具有延续的含义，一般与延续性动词连用。While只表示持续性的动作或状态，不能表示一时性或短暂的动作。例如：   When you arrive in London, please give us a call.

   He entered the room when(while, as)the meeting was going on.

   While she was reading a novel, her mother was cooking the dinner. 

   “in＋动名词”也可以表示时间概念，这种结构相当于由 when或 while 引导的从句in 含有when或 while的意思。例如：  In going through the forest, he found a lot of rare plants.

    （3）No sooner … than 和hardly (scarcely) … when引导

    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。如果No sooner, hardly 或scarcely位于句首，主句要倒装。如：No sooner had he entered the house, than it began to rain.

    （4）Till 和until

①这两个词的用法十分近似，都表示“直到…“，但在句首只能用until 。在肯定句中，主句要用延续性动词；在否定句中，until 或till可以和非延续性动词连用，这时until和before同义。例如：    Until they had finished the work, they did cot go home.

  ② 在表示时间概念时，by与 until不同。by 表示“到…为止“，动作已完成，谓语应是非延续性动词。Until表示“持续到…时候“，谓语应是延续性动词。例如：

    He can finish the work by Saturday.    You’ll have to keep the key until Monday.]

     until, till 引导的从句中不可用shall, will 或would。

    （5）Since   ① since所引导的从句一般要用非延续性动词，主句中用完成时态。例如：

    Since we left school, we have not seen each other.   ② 作介词时，since后要接时间点，不接时间段。例如： He has been writing the book since five years ago.

   （6） As soon as, the moment, directly, immediately, presently, once和 the instant

    这几个连词引导的从句都表示从句动作一发生，主句动作随即发生。例如：

  　She came to the scene immediately she heard of the bad mews.

　  They told me the news the moment they got the message.

2．地点状语从句

    地点状语从句表示在主句中某一动作或状态发生的地点或进行的方向,这类从句通常由Where, wherever或 everywhere引导,可以放在主句前,也可以放在主句后。Where指“在某个地方”，wherever指“在任何一个地方”，everywhere指“每一…地方”。例如：Bamboo grows well where it has plenty of rain.   Wherever you go, whatever you do, I will help you.

    注：在时间状语从句常用一般时表示将要发生的动作。

3． 条件状语从句

条件状语从句表示主句中某一动作或状态是在什么情况或条件下发生的。

   （ 1）if 和unless    if 表示正面的条件，意为“如果”，unless表示反而的条件，意为“除非，如果不”例如：If you’ve got exams tomorrow, why aren’t you studying?

The sports meet will begin tomorrow unless it rains.

    注：在条件状语从句中常用一般时表示将要发生的动作。

    （2） providing, provided (that), supposing, suppose (that), as long as, so long as, on condition that 和in case这些连词（词组）意思相近，有“如果，只要，假如，假使，在…条件下”等意思。例如：  All living things respire as long as they live.

Supposing (that) you fail a second time, didn’t get disappointed, but try again.

  On condition that the liquid is cooled still further, it will turn to a solid.

    注：Providing, provided (that) as long as 的区别是：providing (that) 表示如果某件事发生或是被做，另外一件事将成为可能；as long as表示如果某件事发生或是真实的，另外一件事一定会发生或是真实的。如：You can borrow the car provided (that) you can get it back to me before 10 o’clock. Opportunities are always available so long as one uses his mind.

   （3）Only if和if only

    Only if 引导的从句用陈述语气，意为“只要” if only引导的从句要用虚拟语气，意为“但愿…”，“要是…就好了”。例如：   Only if you have persistence, you can achieve great success.   If only I had wings, I would be able to travel around the world easily.

   （4） Where有时也可以表示条件：Where there is a will, there is a way.（有志者事竟成）。

    There is never peace where men are greedy.（人类贪欲不止，世界和平无望）。

Birth is nothing where virtue is not.（如果没有品德，出身再好也等于零）。

4． 原因状语从句：原因状语从句表示主句中的某一动作或状态所发生的原因。

　 （1）because, since as 和for

because 表示原因的语气最强，常用于回答以疑问词“why”引导的疑问句。 because 从句一般位于主句后面。For引导的从句并不说明主句行为发生的直接原因，只是提供一些有助于说明情况的补充说明，且不可位于主句前。since 表示一种附带的原因，或者表示已知的显然理由，意为“既然”，引导的从句常放在句首。As所表示的理由最弱，只是对主句的附带说明，重点在主句。As通常放在主句前，有时也可改用so引导的分句。例如：

The engine stopped running because the fuel was finished.

   Since you are free today, you had better help me with my mathematics.

   As the day was fine, they decided to go on a trip.

   The day is fine, so they decided to go on a trip.

   There must be no one in the house for the door is closed.

  （2）Seeing (that) , now (that) , considering (that)：这几个连词同since意思相近，都有“鉴于某个事实”的意思。如：He fulfilled his task very well, considering that it was quite difficult.

   (3） in that: In that 与because同义，但它引导的从句不能在句首。例如：

    Theory is valuable in that it can provide a direction for practice.

  （4）not…because:    本结构中not否定的是because引导的整个从句。例如：

    The country is not strong because it is large.（国强不在大）。

5． 让步状语从句

    （1）though, although, even if 和even though

    这四个词（词组）都有“虽然，即使，尽管”的意思，even if 和even though 带有强调的意味，语气较强，though 和although 语气较弱，though 比although 通俗，但不如although 正式。让步状语从句可以放在主句前或主句后。例如：

   Although they did heavy work that day, they were all in high spirits.

   She carries on the job even if she has had a bad cold for several days.

  英语不允许在though 或although从句后用but。如果要强调前后两个部分的对比意义，可以在主句前加上yet或still。例如：

Although she has a lot of money, yet (still) she is not happy.

    （2）no matter how (what, when, which, who, where)

    这几个短语意为“不管怎样（什么，什么时候，哪一个，谁，什么地方）”，例如：

     No matter where party needs us, we will respond to her call.

He keeps taking physical training in the winter no matter how cold it is.

    （3）．Whatever, whenever, wherever. Whoever, whichever however

    这几个词也可以引导让步状语从句，相当于no matter what (when, where , who, which, how)。例如：

   whatever work we do, we should do our best.

   However hard a solid may be, we can change its shape.

    注：however引导让步状语从句时，与它所修饰的词一起放在句首。

    （4）Whether… or (not)

    whether …or (not)提供两个对比的情况，意为“不管…”。例如：

    Whether she comes here or we go there, the topic of discussion will remain unchanged.

   （ 5）where 有时也可以表示让步

    例１：Go where you should, keep on studying.（无论你到哪里，都应该继续学习）。

    例２：Unfortunately, where we should expect gratitude, we often find the opposite.（遗憾的是，虽然我们本应该得到感激却常常得到的是怨恨）。

    （6）．让步状语从句的倒装

    though 引导的让步状语从句可以倒装，也可以不倒装。在倒装句中，though可以用 as或 that代替，但用 as和 that引导的让步状语从句必须倒装。如果名词放提前放在句首，该名词前不可加定冠词或不定冠词。

    常用的句型为形容词（副词，动词，名词，过去分词）＋though (as, that)＋主语＋谓语。例如：  Bravely though we fought, we had no chance of winning.

  Smart as he was, he was not able to solve the problem.

    Child that he was, he had a good command of English.

    （7）．让步状语从句中的虚拟语气

    如果让步从句陈述的是事实，动词用陈述语气；如果从句的陈述情况是假设的，非事实性的，动词常用虚拟语气（用动词原形或Should ＋动词原形）。例如：

    Even though it (should )not succeed, there is no harm in trying.

6．方式状语从句

    （1）as 和just as   二者都表示“如…，犹如…，正如…”。just as 比as强调的语气更强。例如：   In the early days, people could not count as we do now.

   Most plants need sunlight just as they need water.

    （2）as if 和as though

    as if 或as though从句可以用陈述语气，表示可能符合事实的情况；也可以用虚拟语气，表示不符合事实或与事实相反的情况，意为“好像，仿佛”。例如：

    Some rocks sparkle with an unusual brilliancy as if they contained gold.

    It looks as though it is going to rain.

    （3） according as 和according to

    according as 是连词词组，后面接句子，意思是“以…方式”，“按…来” according to是介词词组，后面只能接单词或词组，意思是“根据…”，“随着…不同而不同”例如：

    1) The thermometer rises or falls according as the air is hot or cold.

    2) According to the timetable, the train gets in at 8:30.

7．比较状语从句

    （1）As… as    这种结构可以用于同等程度的比较，否定句用not so (as) …as。例如：

A pound of cotton weighs as mush as a pound of iron.

    Sound does not travel so fast in gases as in liquids.

    （2）as 和than

    as 和than连接的比较状语从句常常省去同主句相同的部分，只留下相比的部分。例如：

     Bill is as tall as Bob (is).     Steel is more useful than iron (is ).

    （3）The… the…   the …the…后面分别跟形容词或副词的比较级，意思为“越…越…”。例如：   The faster, the better.   The higher the airplane flies, the thinner the air is.

8．目的状语从句

   （ 1）so that 和in order that     二者都表示“为了，以便”。so that 较常用，一般放在主句之后。in order that 用于正式文体，引导的从句可放在主句前面或后面。例如：

    She takes notes carefully in class so that she may use them when she reviews her lessons after class.

    In order that the motion of a body can be changed, an additional force is needed.

    so that 中的so有时可省略。例如：

We are working hard that we may build our country into a powerful socialist state.

     so that 有时也可分开。例如：

    So live your life that old age will bring you no regrets.（好好生活以使老年无悔）。

    （3）lest, for fear that 和in case

    这三个连词（词组）意思是“以防，以免”。lest, for fear that后的从句一般要用虚拟语气，形式为“ should＋动词原形” in case从句一般用虚拟语气，但有时也可以用陈述语气。例如：    We must hurry off lest we should miss the bus.

    Don’t forget your umbrella in case it should rain. Phone me in case you meet problems.

9．结果状语从句

    结果状语从句表示主句中某一动作或状态所产生的结果，常常位于主句之后。

    （1）so …that 和such …that

    这两个词组意为“如此…以至”常用结构如下：

    so＋adj / adv＋that       so＋adj＋a (an)＋n＋that       such＋a (an)＋adj＋n＋that

    例１：The box is so heavy that nobody can move it away.

    例２：It is so heavy a box that nobody can move it away.

    例３：It is such a heavy box that nobody can move it away.

   （ 2）that    在结果状语从句中that意为“因而，从而，所以，结果”。例如：

Something may be wrong that the machine has stopped running.