英语的“be”是个特别动词;有些语言，如中文和马来文，并没有“be”这样的动词。

“Be”除了原形的“be”之外，还有另外七种形式：am, is, are, been, being, was, were.

在句子中，“be”可以是主动词(The Principal Verb)或助动词(The Auxiliary Verb).

当主动词时，“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：

1. The man is a science teacher.

2. Mary’s new dresses are colourful.

3. I have been there before.

4. Mother is in the kitchen now.

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：

5. Is the man a science teacher?

6. Are Mary’s new dresses colourful?

7. Have I been there before?

8. Is mother in the kitchen now?

当“be”要在祈使句中出现时，它必须借重助动词“do”或“don’t”之助，如：

9. Don’t be silly!

10. Do be obedient!

11. Don’t be a fool!

“Be”有两种缩写法，如下：

12. He’s not……/He isn’t……

13. You’re not……/You aren’t……

但“am + not”的缩写法只有一个：

14. I’m not.

有人用“ain’t”, 但这并不是标准英语。

谈过了“be”作主动词的功能，现在看看“be”作助动词时，有些什么用法：

1.“Be + 现在分词”以组成进行式时态(Continuous Tenses)，如：

15. Tony’s maid is washing his new car.

16. The children are playing in the field.

17. Samuel was eating when I came in.

18. We have been living here since 1959.

2.“Be + 过去分词”以组成被动语态(The Passive Voice),如：

19. Her money in the drawer was stolen.

20. A number of good jobs are taken up byforeigners.

21. David studied in Taiwan but has been trained as a language lecturer in America.

22. Can all the wonderful birds be found in our Bird Park?

23. The disobedient boy was told to stand out- side the classroom.

24. Steps are being taken to reduce traffic con- gestion during peak hours.

25. Dishonest students will be immediately dealt with.

从上面例子看，“be”这动词外貌平凡，但内涵丰厚。如果没有“be”，补足语的桥梁断了。如果没有“be”,何来进行式时态和被动语态?缺了这几样重要的句式，英语还像英语吗?