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.