1、状语从句一 时间状语从句1 当when引导时间状语从句时，从句的动作可以与主句的动作同时进行，用while或as代替；也可以略先于主句动作，用as soon as代替；也可以略后于主句的动作，用before代替。I like perfect quietness when I am working.When they arrived，it started to rain.The train had left when he hurried to the station.有时when引导的时间状语从句，在意义上与主句是并列关系，when相当于and then或and suddenly，它与主句之间
2、常用逗号分开。 I stayed till noon，when I went home. I was taking a walk，when I came across a friend of mine.when引导从句有时具有让步、原因的意义。 He usually walks when he might ride. Why did not you do it when you knew it would do you good？2 当主句的谓语是现在完成时或过去完成时时，表示“自从以来”的时间状语从句用连词since引导，不能用after。若用after引导从句，则主句中的谓语不能用完成时。
3、He has been abroad since he graduated from the university.He went abroad after he graduated from the university.since从句中的谓语根据具体情况可以用一般过去时或现在完成时。 I have known her since we were children. I have known her since I have lived in this street.3 the moment，the minute，the instant和the second均可以用作连词，解作“一（就）”，
4、相当于as soon as。The moment I saw you I knew you were angry with me.I will tell her the minute she gets here.I loved you the instant I saw you.The second he heard the news，he told it to me.4 在英国英语中，immediately，instantly和directly均可以用作连词，解作“一（就）”，相当于as soon as。Immediately his intentions are understood，he
5、 may leave.I recognized her instantly I saw her.Directly I had done it，I knew I had made a mistake.二 地点状语从句当where和wherever用作连接副词时，前者解作“在（到）地方”，后者解作“无论在（到）哪里”。 Where there is a will，there is a way. Wherever he goes，he is welcome.三 原因状语从句1 用because引导的原因状语从句往往回答why的问题，语气最强，通常放在主句之后，但是在现代英语中也可以放在主句之前。si
6、nce和as所引导的原因状语从句不回答why的问题，语气要比because弱，通常放在主句之前。since比as稍微更正式一些，它所引导的从句的内容往往对方已经知道，解作“既然”。for是并列连词，语气最弱，通常放在主句之后，它所陈述的理由只是起补充说明作用。He cannot come to help us now because he is busy with some other work.As you are tired，you had better have a rest.Since you ask，I will tell you.It must have rained last n
7、ight，for the ground is wet.有时用because和as都可以，但是侧重点不同：用as时，强调的是主句部分；用because时，强调的是从句部分。 As my secretary is away at present，I have a great many extra letters to answer. I have a great many extra letters to answer because my secretary is away at present.2 seeing （that）和now （that）也可以用于引导原因状语从句，解作“既然，由于”，
8、其用法与as和since相同，通常要放在主句之前。Seeing （that） he is ill，we will do the work for him.Now （that） I am well again，I can go on with my work.3 在强调句型“It isthat”中，如果被强调的是原因状语从句，则该从句只能用because引导。It was because the car was so small that he sold it.四 目的状语从句1 引导目的状语从句的连词常用so that，in order that和that。so that比in order t
9、hat更为常用，尤其是在非正式文体中；that常用在非常正式的文体中。在这种主从句中，如果主句是现在时或将来时，则从句中可以用表示将来含义的现在时。此外，在这种目的状语从句中常含有情态动词can或may。We ought to write to him in order that he does not feel we are hiding things from him.You must practice daily so that you will win the race.Lets work hard that we may make greater progress.I will le
10、ave a note so that they can know where I have gone.当主句是过去时时,以so that，in order that引导的目的状语从句中常用should或could，也可以用would或might，但是might只用在非常正式的文体中。 She spoke loudly so that all could hear her. He came in quietly in order that he should not wake his wife. Mary talked to the shy girl so that she would not
11、feel left out. They climbed higher so that they might get a better view.2 连词lest，for fear （that）也可以引导目的状语从句，相当于“so thatnot”，解作“惟恐、生怕、以免”，但是lest的用法较为古旧，现代英语中多用for fear （that）或so thatnot。在lest和for fear （that）所引导的从句中，谓语动词要用虚拟语气“should+原形动词”或原形动词。I hid the book lest he （should） see it.= I hid the book f
12、or fear （that） he （should） see it.= I hid the book so that he should not see it.3 当in case引导目的状语从句时，解作“免得，以防（万一）”，相当于lest或for fear that。但是in case所引导的从句中可以用陈述语气（表示事情发生的可能性较大），也可以用虚拟语气（表示事情发生的可能性较小），在谈及过去的事情时，常用虚拟语气“should+原形动词”，尤其在正式文体中。You had better take your umbrella in case it rains.I took a coup
13、le of notebooks in case I should have time to do some writing.有时，in case相当于if，引导条件状语从句。 In case he comes，let me know. =If he comes，let me know.五 结果状语从句1 that和so that都可以用来引导结果状语从句，但是that前不能加逗号，而so that前常加逗号。I received my wages yesterday，so that I can now pay what I owe you.What has happened that you
14、all look so excited？ so that既可以引导目的状语从句，又可以引导结果状语从句。两者的区别是：引导目的状语从句时，so that前一般不能加逗号，后面常有情态动词can，may，should；引导结果状语从句时，so that前常有逗号，后面很少有情态动词。但是这种区别并不是绝对的，so that所引导的究竟是目的状语从句还是结果状语从句要取决于上下文。2 sothat，suchthat也可以用来引导结果状语从句。so是副词，与形容词或另一个副词连用；such是形容词，与名词连用。It was so hot that nobody wanted to do anythi
15、ng.He ran so fast that I could not catch him.It was such a hot day that nobody wanted to do anything.六 条件状语从句1 当unless用来引导条件状语从句时，相当于“ifnot”，前者的语气要比后者重，通常两者可以互换。He will accept the job unless the salary is too low. = He will accept the job if the salary is not too low.当表达“主句的行为如果不受到从句行为的阻碍定能发生”时，可以用u
16、nless或ifnot；当表达“主句的行为是由于从句行为的缘故而发生”时，只能用ifnot，不能用unless。 I will be quite glad if she does not come this evening. She would be pretty if she did not wear so much make-up.2 由as（so） long as，provided （that），providing （that），on（upon） condition that，on the understanding that， suppose（supposing） （that），on
17、the supposition that都可以用来引导条件状语从句，相当于if。此外，还有but that（若不），as（so） far as（就），granted（granting） （that）（假定）。I shall go as long as he asks me.You can fly to London this morning provided you do not mind changing planes in Paris.Supposing that he did not come，who would replace him？But that I saw the machin
18、e，I could not have imagined how efficiently it works.He is a quite conscientious man so far as I know.Granting that you are telling the truth，can you prove it？七 让步状语从句1 由连词though（多用于口语），although（多用于书面语），even if（多用于口语），even though（多用于书面语），granted（granting） （that），whetheror都可以用于引导让步状语从句。Although he is
19、 young，he is well-mannered.You must not be conceited even if you have achieved great successes.Granted that they were not doing it in the right way，you were not right in taking everything on yourself. All living things，whether they are animals or plants，are made up of cells.2 让步状语从句还可以由no matter who
20、（what，which，when，where，how）=whoever（whatever，whichever，whenever，wherever，however）以及no matter whether引导。It is not true，no matter who may say so. = It is not true，whoever may say so.No matter what you may do，do it yourself. =Whatever you may do，do it yourself.No matter which book you may choose，you wi
21、ll be pleased. =Whichever book you may choose，you will be pleased.You are always welcome no matter when you come. = You are always welcome whenever you come.No matter where you may go，no one will welcome you. =Wherever you may go，no one will welcome you.No matter how hard he tries，he never seems abl
22、e to do the work satisfactorily. =However hard he tries，he never seems able to do the work satisfactorily. No matter whether you agree or not，I shall pay him the price he asks. 上述句子中的may在口语中可以省略。3 当as用于引导让步状语从句时，句子要倒装；其他连词引导让步状语从句时，句子不能倒装。但是though有时也取代as的这种用法，这种句子常用于正式文体中。Poor as he was，he was hones
23、t.Bravely though they fought，they had no chance of winning.八 方式状语从句1 由连词as，just as，according as可以引导方式状语从句。Henry did the work as it ought to be done.The earth goes around the sun just as the moon goes around the earth.I will go or stay according as the situation requires.2 由as if（=as though）也可以引导让步状语
24、从句，此时从句常用虚拟语气。He talks as if he were a scholar.He works with such enthusiasm as though he never knew fatigue.九 比较状语从句1 比较状语从句常用asas，not so（as）as，not suchas，morethan，lessthan引导。这种状语从句常省略某些成分。He is as busy as a bee.She does not study so hard as （she did） before.This work is not as easy as you think.Th
25、e question was not such an easy one as I thought.Light travels faster than sound.It rains more often in summer than in winter.This problem is less important than that one.2 由“the morethe more”也可以引导比较状语从句。在这种结构中，more代表形容词或副词的比较级，前一个“the more”是从句，后一个“the more”是主句，主句和从句中的语序都需要倒装。有时也可以将主句放在从句之前，但主句的语序应该改变为：主语+谓语+（the） more，从句的语序保持不变，即（the） more+主语+谓语。The higher you go，the less dense air becomes.=Air becomes （the） less dense the higher you go.
