解放军文职考试英语辅导：be动词用法

当做主动词时，“be”在性质上属于接系动词(The Linking Verb), 后面要有名词、形容词、地方副词或短语作补足语(The Complement)。例如：

The man is a science teacher.

这个男子是一位科学教师。

Mary's new dresses are colourful.

玛丽的新衣服色彩鲜艳。

I have been there before.

我以前去过那里。

My mother is in the kitchen now.

我妈妈现在在厨房里。

这四个都是陈述句，可以变成疑问句，方法简单，把主语和“be”或助动词对换位置即可：

Is the man a science teacher?

Are Mary's new dresses colourful?

Have I been there before?

Is mother in the kitchen now?

当“be”要在祈使句中出现时，陈述句可借助助动词“do”，否定句必须在前加上助动词“don't”，如：

Don't be silly!

Do be obedient!

Be careful!

Don't be a fool!

“Be”有两种缩写法，如下：

He's not...../He isn't....

You're not...../You aren't...

但“am + not”的缩写法只有一个：

I'm not.