英语中的动词按照其词义和在句中的作用可分为四类：实义动词、连系动词、助动词和情态动词。

【兄弟之一】 实义动词

实义动词含有实在意义，表示动作或状态，在句中能独立作谓语。

实义动词分为及物动词和不及物动词两种。及物动词（如：want, like, help, ask, teach等）之后能直接接宾语。如：We like English.

不及物动词（如：go, come, live, swim等）之后不能接宾语。如：She lives in Chongqing.

【兄弟之二】 连系动词

连系动词有一定的词义，但不能独立作谓语，必须与表语一起构成谓语。主要的连系动词有be（是）, become（成为）, smell（闻起来）, sound（听起来）, feel（感觉）, look（看起来）, get / turn / grow（变得）等。如：Cotton feels nice and soft.

【兄弟之三】 助动词

助动词本身没有词义，不能独立作谓语，只能和主要动词一起构成谓语。已学过的助动词有be, do, have, will, shall等。下面分述如下：

1） be有am, is, are, was, were五种形式。

am, is, are用于现在进行时、be going to结构中。如：

They are listening to the teacher.

was, were用于过去进行时。如：

He was doing his homework this time yesterday.

2） do有does, do, did三种形式。

do 和does常用于一般现在时的否定句和疑问句中，did用于一般过去时的否定句和疑问句中。如：

She doesn't do her homework in the evening.

Do you want a go? Yes, I do.

I didn't go to the library yesterday.

What did you do last Sunday?

3） will, shall

will/ shall用于一般将来时中。如：I shall write you a letter next month.

Will you go to the zoo with me?

【兄弟之四】 情态动词

情态动词具有一定的词义，但不能独立作谓语，只能和动词原形一起作谓语，没有人称和数的变化。常见的情态动词有can, may, must, need等。如：You must look after your clothes.

[巩固练习]：

句型转换。

1. We'll have a class meeting this afternoon.（改为一般疑问句）

_________ you _________ a class meeting this afternoon?

2. He has to buy a dictionary for his daughter.（改为否定句）

He_________ _________to buy a dictionary for his daughter.

3. Bruce bought a dictionary yesterday. （改为否定句）

Bruce_________ _________a dictionary yesterday.

4. Mr Smith does morning exercises every day.（改为一般疑问句）

_________ Mr Smith _________ morning exercises every day?

参考答案：1.Will, have 2. doesn't have 3. didn't buy 4. Does, do