初中英語語法大全：連詞

三 連詞比較

I　and 與or

1) 并列結(jié)構(gòu)中，or通常用于否定句，and用于肯定句。

2) 但有時and 也可用于否定句。請注意其不同特點：

There is no air or water in the moon.

There is no air and no water on the moon.

在否定中并列結(jié)構(gòu)用or 連接，但含有兩個否定詞的句子實際被看作是肯定結(jié)構(gòu)，因此要用and。

典型例題

---I don't like chicken ___ fish.

---I don't like chicken, ___ I like fish very much.

A. and; and　 B. and; but　C. or; but　D. or;and

答案C。否定句中表并列用or, but 表轉(zhuǎn)折。

判斷改錯：

(錯) We will die without air and water.

(錯) We can't live without air or water.

(對) We will die without air or water.

(對) We can't live without air and water.

3 )表示選擇的并列結(jié)構(gòu)

(1) or　意思為"否則"。

I must work hard, or I'll fail in the exam.

(2) either…or　意思為"或者……或者……"。注意謂語動詞采用就近原則。

Either you or I am right.

判斷改錯：

(錯) They sat down and talk about something.

(錯) They started to dance and sang.

(錯) I saw two men sitting behind and whisper there.

(對) They sat down and talked about something.

(對) They started to dance and sing.

(對)I saw two men sitting behind and whispering there.

解析：

第一句： and 連接兩個并列的謂語，所以 talk 應改為 talked。

第二句：and 連接兩個并列的動詞不定式，第二個不定式往往省略to，因此sang 應改為 sing。

第三句：and 連接感觀動詞saw 后面的用作的賓補的兩個并列分詞結(jié)構(gòu)，因此whisper應改為whispering。

注意：and 還可以和祈使句或名詞詞組連用表示條件。(or也有此用法)

Make up your mind, and you'll get the chance.

= If you make up your mind, you'll get the chance.

One more effort, and you'll succeed.

= If you make one more effort, you'll succeed.

II　but表示轉(zhuǎn)折，while表示對比。

Some people love cats, while others hate them.

典型例題

--- Would you like to come to dinner tonight?

--- I'd like to, ___ I'm too busy.

A. and　 B. so　 C. as　 D. but

答案D。but與前面形成轉(zhuǎn)折，符合語意。而表并列的and，結(jié)果的so，原因的as都不符合句意。

III so, therefore

He hurt his leg, so he couldn't play in the game.

注意：

a. 兩個并列連詞不能連用，但therefore, then, yet.可以和并列連詞連用。

You can watch TV, and or you can go to bed.

He hurt his leg, and so / and therefore he couldn't play in the game.

b. although… yet…，但although不與 but連用。

(錯)　Although he was weak, but he tried his best to do the work..

(對)　Although he was weak, yet he tried his best to do the work.