英语词类中的连词

连词是连接单词、短语、从句或句子的一种虚词，在句子中不单独作句子成分，一般不重读。从意义上来说， 可以分为并列连词和从属连词。

一、并列连词

并列连词用来连接互为并列关系、互不从属的单词、短语和句子。

1、表示而且：and, both... and..., not only...but also...

She wore her new coat, a fine silk cap and a pair of leather shoes.

The office is both light and airy.

Not only did he make a promise, but also he kept it.

2、用于对比，表示转折：but, yet, while, still, however, nevertheless, whereas

The car was quite old but in good condition.

She is old and weak, yet she works hard.

It is spring now, still it is rather cold.

He often met with difficulties, nevertheless he went on working.

3、表示选择: or/or else(否则), otherwise, either... or...

Hurry up, or else you’ll be late.

The tumor must be resected, otherwise it will become malignant.

Either you or I must take part in the consultation.

4、表示因果：so, for, therefore, thus, hence

The rain began to fall, so we went home.

You had better put on your cotton jacket, for it is rather cold outside.

He studied hard, thus he got good marks.

二、从属连词

从属连词用来连接主句和从句，可分为两类：引导名词性从句的从属连词和引导状语从句的从属连词。

1. 引导名词性从句（主语从句、表语从句、宾语从句、同位语从句）：that, whether if.

That the old man is still alive is known to all of us.

The question is whether she will come in time.(是否)

I wonder if her answer to this question is correct.(是否)

2. 引导状语从句：after, before, as, when, while, since, until, till, although, though, if, even if, unless, lest, because, than, so that, as soon as, as long as, as if, as though, so... that, such... that, as...as, so... as.

We had a rest after we finished the task.

A man will die if he is cut off from fresh supply of oxygen.

She didn’t attend the meeting because she had something more important to do.

I remember everything about the accident as if it happened yesterday.