五、连词

连词是虚词，不能在句中单独担任成分，只起连接作用。按其用法，连词可分为两大类：并列连词和从属连词。

并列连词

连接具有并列关系的词、短语或句子。

⒈ 并列关系：and，not only...but also...，both...and...，neither...nor...

如：I used to live in Paris and London.

Both Jane and Jim are interested in fishing.

The weather here is neither too cold nor too hot.

She is not only kind but also honest.

⒉ 转折关系：but，yet，while（然而），when（然而，偏偏）

如：The car is very old but it runs very fast.

The problem was a little hard,yet I was able to work it out.

The winter in Beijing is very cold while that of Kunming is warm.

Why did you borrow the book when you had one?

⒊ 选择关系：or，not...but...，either...or...

如：Would you like to live or would you like to stay?

He is not a teacher but a writer.

You can come either on Saturday or on Sunday.

⒋ 因果关系：for

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

The leaves of the trees are falling. for already autumn.

5. 区别

① and和or

⑴ 并列结构中，or通常用于否定句，and 用于肯定句。

⑵ 但有时and 也可用于否定句。请注意其不同特点：

如：There is no air or water in the moon.

There is no air and no water on the moon.

在否定中并列结构用or连接，但含有两个否定词的句子实际被看作是肯定结构，因此要用and。

判断改错：

（错)We will die without air and water.

（错）We cait live without air or water.

（对）We will die without air or water.

（对)We cant live without air and water.