2状语从句

状语从句

1. 状语从句有九大类：时间、地点、原因、目的、结果、条件、让步、比较、方式。

本质上说，状语从句就是用不同的连词将几个分句连接起来，以表达分句之间的逻辑关系。

I’ve bought my umbrella in case it rains.

I’ve bought my umbrella because it rains.

I’ve bought my umbrella so that I don’t get wet.

I’ve bought my umbrella even though it’s not raining.

You don’t need an umbrella unless it’s raining.

学习状语从句的关键是要掌握引导九类状语从句的有关连接词。

2. 状语从句的省略

在同时满足一下两点的情况下：1）当主句的主语和从句的主语一致：2）从句谓语中含有be动词。可将从句的主语和be动词省去。这种省略主要常见于时间、地点、条件、及让步状语从句。

a.Metals expand when (they are) heated and contract when (they are) cooled.

b.When (he was) a student in the university, he read a lot.

c.While (he was) waiting, he took out a megazine to rea

d.

d. A tiger can’t be tamed unless (it is) caught very young.

e.When I was ten years old, my family moved to city.

两个主语不同，故从句不可用省略形式。

1.时间状语从句要用一般现在时表示将来

a.I will speak to him when he arrives.

b.I will tell him about it when he comes back.

2.when

意思相当于：at the time(在……时刻)，从句谓语动词通常是短暂动词，表示某一时刻的动作。注意主句和从句的事态

a.When I arrived, he was talking on the phone.

b.When I got there, he had already left.

c.When I got there, he left the office,.

从句也可接延续动词，这时从句往往用过去进行时态，表示某一时间段内发生的动作。

d.The doorbell rang when I was telephoning.

3.while

意思相当于：during that time(在…期间)，表示某一时间段内发生的动作，因此，从句谓语动词通常只接延续动词。

a.The phone rang while I was taking my bath.

b.The doorbell rang while we were watching tv.

4.until

1）当主句谓语动词是延续动词时，通常用肯定形式。

a.Wait until he comes back.

b.We’ll stay here till it stops raining.

c.Until I came back, he was waiting for me at my home.

2）若主句谓语动词是短暂动词，则要用否定形式。这就是我们常说的“not…until”（直到……才）的结构。

a.I did not realize how special my mother was until I became an adult.

b.Icecream did not reach America until about the middle of the eighteenth century.

c.I didn’t go to bed until 12 o’clock last night.

d.He didn’t leave the office until his boss came back.

3)until置于句首：

a. Until he saw his mother, the little boy didn’t smile.

b.Until recently I began to learn what had happened.

4) 我们还可以把not…until 变成倒装句型：

a. Not until 12 o’clock last night did I go to bed.

b. Not until his boss came back did he leave the office.

5）强调结构：

a.It was not until he saw his mother that the little boy smiled.

b.it was not until recently that the exact time of dying was important.

注意：

1）until 后接的动词常是短暂性动词。

2）在not until倒装结构中，需部分倒装的是主句中的谓语动词，而非从句中的谓语动词。

Not until she had arrived home did she remember her appointment with the doctor.

3)倒装结构演化成强调结构时，则主句谓语不再采用倒装形式。

A.It was not until she had arrived home that she remembered her appointment

with the doctor.

5.表示“一……就……”

1)表示“一……就……”的连词有：as soon as, once, immediately, the moment,the minute,the instant,directly,instantly。这些连词后面通常都是接短暂动词，表示一点动作。

a.We will leave as soon as it stops raining.

b.Once it stops raining, we will leave.