高考英语语法系统讲解之十一状语从句专题学案

高中英语语法系统讲解之十一

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.

○3till，until（not …until / till …）“直到……才”

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.