be 的用法口诀
我用am，你用are，is连着他，她，它;
单数名词用is，复数名词全用are。
变疑问，往前提，句末问号莫丢弃。
变否定，更容易，be后not莫忘记。
疑问否定任你变，句首大写莫迟疑。
be动词的用法：be (be/is/are/am/was/were)
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
英语的“be”是个特殊动词;有些语言，如马来文等，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)
例句对照
【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.
这个男子是一位科学教师
2. Mary's new dresses are colourful.
玛丽的新衣服色彩鲜艳
3. I have been there before.
我以前去过那里
4. My mother is watching TV in the room.
母亲现在在客厅看电视
【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.】“情态动词+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.