have的用法
1）have +过去分词,构成完成时态.例如：
He has left for London. 他已去了伦敦.
By the end of last month,they had finished half of their work.上月未为止,他们已经完成工作的一半.
2）have + been +现在分词,构成完成进行时.例如：
I have been studying English for ten years.我一直在学英语,已达十年之久.
3）have +been +过去分词,构成完成式被动语态.例如：
English has been taught in China for many years.中国教英语已经多年.
do 的用法
1）构成一般疑问句.例如：
Do you want to pass the CET? 你想通过大学英语测试吗?
Did you study German? 你们学过德语吗?
2）do + not 构成否定句.例如：
I do not want to be criticized.我不想挨批评.
He doesn't like to study.他不想学习.
In the past,many students did not know the importance of English.
过去,好多学生不知道英语的重要性.
3） 构成否定祈使句.例如：
Don't go there. 不要去那里.
Don't be so absent-minded. 不要这么心不在焉.
说明：构成否定祈使句只用do,不用did和does.
4）放在动词原形前,加强该动词的语气.例如：
Do come to my birthday party. 一定来参加我的生日宴会.
I did go there. 我确实去那儿了.
I do miss you. 我确实想你.
5）用于倒装句.例如：
Never did I hear of such a thing.我从未听说过这样的事情.
Only when we begin our college life do we realize the importance of English.进了大学以后,我们才认识到英语的重要性.
说明：引导此类倒装句的副词有never,seldom,rarely,little,only,so,well等.
6）用作代动词.例如：
---- Do you like Beijing? --你喜欢北京吗?
---- Yes,I do. --是的,喜欢.（do用作代动词,代替like Beijing.）
He knows how to drive a car,doesn't he?他知道如何开车,对吧?
