判断改错：

(错) They sat down and talk about something.

(错) They started to dance and sang.

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

(对) They sat down and talked about something.

(对) They started to dance and sing.

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

解析：

第一句： and 连接两个并列的谓语，所以 talk 应改为 talked。

第二句：and 连接两个并列的动词不定式，第二个不定式往往省略to，因此sang 应改为 sing。

第三句：and 连接感观动词saw 后面的用作的宾补的两个并列分词结构，因此whisper应改为whispering。

注意：and 还可以和祈使句或名词词组连用表示条件。(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表示转折，while表示对比。

Some people love cats, while others hate them.

典型例题

--- 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与前面形成转折，符合语意。而表并列的and，结果的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. 两个并列连词不能连用，但therefore, then, yet.可以和并列连词连用。

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不与 but连用。

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

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

IV 比较so和 such

其规律由so与such的不同词性决定。such 是形容词，修饰名词或名词词组，so是副词，只能修饰形容词或副

词。so 还可与表示数量的形容词many，few，much， little连用，形成固定搭配。

so + adj.　　　　　　　　　such + a(n) + n.

so + adj. + a(n) + n.　　　such + n. (pl.)

so + adj. + n. (pl.)　　　 such +n. (pl.)

so + adj. + n. [不可数]　　such +n. [不可数]

so foolish　　　　　　　　 such a fool

so nice a flower　　　　　 such a nice flower

so many/ few flowers　　　 such nice flowers

so much/little money.　　　such rapid progress

so many people　　　　　　 such a lot of people

so many 已成固定搭配，a lot of 虽相当于 many，但 a lot of 为名词性的，只能用such搭配。

so…that与such…that之间的转换既为 so与such之间的转换。

Eg :The MP3 cost me ________ money that I ccouldn't afford to buy it .

A .so much .B .such much C .so many

D . such many .(Key :A )

注意:too .... to .. ,so ..... that .... , such .... that .... , enough ..... to ...., 的互换.

so that to = in order to /that 的用法.

Eg A .He is too young to go to school.

B .He is ____ a young boy _____ he ____ go to school .

C .He is ____ young ____ he ____ go to school .

D .He isn't ______ _______ ______ go to school (Keys :B :such , that , can't C :so ,that ,can't .D : old ,enough to )

易错分析：

①关于not…until

He stayed there until it was very late.

句中，stay是可延续性动词，所以不用not。

He didn't leave until it was very late.

句中，leave是不可延续性动词，所以用not

②because, so;although, but

上面已经提到，because和so及although和but不连用。

例如:

Because he was late, he didn't catch the first bus.

一定不可以说

Because he was late, so he didn't catch the first bus.