be动词的用法是什么?

be动词意思和用法很多，一般的意思是：是，此种用法，有多种变化形式，is，am，are，was，were，being，been，to
be.另外，be动词还有成为的意思。根据句子中不同的人称、数和时态，应该选择相应的be动词。
要看句语的时态:
如果是一般过去时,就用was/were
如果是一般现在时,就用am/is/are
如果是一般将来时,就用will
be

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.

be
[bi:]
vi
现在时 I am, you are, he is, we are, you are, they are （缩略式 I'm, you're, he's, we're, you're, they're）, （否定缩略式 I'm not, isn't, aren't）, 过去时 I was, you were, he was, we were, you were, they were （过去时否定缩略式 wasn't, weren't）, 过去分词 been, 现在分词 being

be等于"是",第一人称变为am,第二人称,主语为复数为are
第三人称用is