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。
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”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. My mother is watching TV in the room.
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?
9. Don't be silly!
10. Do be obedient!
11. Don't be a fool!
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.
【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.