在什么情况下要用BE动词，在什么情况下动词后面要加ing【除现在进行时】

【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.