高中英语语法系统讲解之十一状语从句

状语从句

状语从句在句中作状语，修饰主句中的动词、形容词或副词等，有时修饰整个主句。

状语从句放在主句之前时，常用逗号分开；放在主句之后，一般不用逗号。状语从句按其意义和作用分为时间、条件、原因、让步、目的、结果、方式、比较、地点等9种。

1. 时间状语从句

时间状语从句可放在句首、句中或句尾。常用when，while，as，after，before，since，until，once，as soon as，the minute / moment“一……就……”，hardly … when，no sooner …

than“刚……就……”等连接词引导。

○1连词when，while，as都表示“当……的时候”，但是when引导的从句的动作和主句的动作可以同时发生，也可以先后发生；用as，while时则强调主句和从句的动作同时发生。如While I was reading, he came in.

As he walked along the street, he sang happily.

但当从句表示“随时间推移”时，只能用连词as，不能用when或while。

如As time goes on, I like to speak English more and more.

○2从属连词as soon as，immediately，directly，the moment，the minute，no sooner … than …，hardly / scarcely … when …，once引导的从句都表示从句的动作一发生，主句的动作随即就发生，意为“一……就……”，从句中用一般时态代替将来时态。

如Once you remember it, you’ll never forget it.

The moment I heard the voice, I knew father was coming.

No sooner had we arrived at the station than the train left.

温馨提示：as soon as，the moment引导的从句表示“一……就……”；no sooner … than …，hardly … when引导的从句表示“刚……就……”。主句中的动词一般用过去完成时，从句用过去时；而且主句一般倒装，把助动词had提到前面。

如As soon as I finish the work, I’ll go to see you.

Hardly had I entered the room when I heard a loud noise.

○3

温馨提示：○1till不可以置于句首，而until可以置于句首。如Until you told me I had no idea of it. ○2如果将“not until …”结构放在句首，那么主句要写成倒装句。如Not until we pointed out their fault to them did they realize it.

○4every time，each time，next time等名词短语用来引导时间状语从句，表示“每当……，每次……，下次……”。如Every / Each time I was in trouble, he would come to help me out.

Next time you come, do remember to bring your son here.

2. 条件状语从句

从句可置于句首或句尾，有时还可放在主语和谓语之间。常用的引导词有if，unless，as long as，so long as，provided，suppose / supposing，on condition（that）等。

如I may not come see you recently unless I can complete the project ahead of time.

We can surely attain our goal as long as we are united as one.

温馨提示：条件状语从句分为真实条件句和非真实条件句。○1真实条件句：假设的情况

有可能发生的条件句叫真实条件句，用陈述语气。如He will not leave unless it is fine tomorrow. I’ll write to your parents if you’re late again. ○2非真实条件句：假设的情况完全是一种假设或发生的可能性不大的条件句叫非真实条件句，用虚拟语气。如If it were not raining now, I would not be staying at home.

3. 原因状语从句

由从属连词because，as，since，for，now that“既然”等引导。

如Don’t scamp your work because you are pressed for time.

As the weather was fine, I opened all the windows.

Since we live near the sea, we can often go swimming.

It must have rained last night, for the ground is wet.

Now that you have known the truth, I needn’t keep it secret.

温馨提示：○1because引导的最主要、最直接而且不为人知的原因，语气最强。回答用why提问的句子只能用because引导。其引导的从句可放在主句之前或之后。如You shouldn’t get angry just because some people speak ill of you. ○2as引导的是较为明显的原因，语气较because弱，常常位于主句之前。如As he didn’t know much English, he often took

a dictionary with him. ○3since引导的是明摆着的、大家都知道的事实，也常位于主句之

前。如Since a lot of people make mistakes in life, you’d better give him a chance. ○4for引导的是一种推测或附加说明，语气最弱，总是位于主语之后，且常用逗号与主句隔开。

如We must start early, for we have a long way to go.

4. 让步状语从句

常有though，although，even if / though，as，however，whatever，no matter，whether …

or …等从属连词引导。

如Though it was very cold, she went out without an overcoat.

I won’t mind even if / though he doesn’t come.

Young as he is, he knows a lot.

However tired you are, you must finish the work in time.

Whatever / No matter what you do, do it well.

Whether it shines or rains, I will go tomorrow morning.

温馨提示：由although（though，as）引导的让步从句，主句不能用but。

由as引导的让步状语从句，须将作标语的形容词、名词（前不用冠词）、表示程度的副词（如much）或动词原形放在句首，构成部分倒装句式。

如Child as he is, he knows much about his family.

Much as I love her, I won’t marry her.

Try as he might, he failed a second time.

5. 目的状语从句

常用的引导词有so that，in order that，lest，in case，for fear等。

We should do our utmost in order that we may be able to over fulfill the task.

You’d better leave your phone number so that I can call you before I come next time.

温馨提示：表示肯定----so that，in order that意为“为了使……发生（目的是……，为的是……）”；表示否定----lest，in case，for fear意为“为了使……不发生（以免，以防）”

如He took his umbrella with him lest it should rain.

I’ll keep a seat for you in case you should change your mind.

6. 结果状语从句

常用so that，so … that，such …that等引导。