How long did you study before you qualified.为什么不是have you studied?

How long ago did you start school? how,spend,did,there,long,you(?) How long did you stay there? how long did you ____ it how long did you stay in Beijing? how long did you stay there?能否改为 how long did you stay at there? How long did you Spend (do) your homeHow long did you Spend (do) your homework how long haveyoubeen和how long did you skate?有什么区别?how long haveyoubeen和 how long did you skate?有什么区别? How long have you been skating?与How long did you skate?的区别 how long ago did you start school?怎么回答? How long did you stay there? 应该怎么回答 英语改错“How long did you find it? How long did you spend ---(do)sport yesterday? how long完成时how long不是问一段时间的吗?为什么可以用How long did you stay? how long haveyoubeen和how long did you skate?什么区别? How long did you sleep为什么用did ,不能用were you sleeping 或 asleep. -how/when /where/how long did you guess?-the way you speak.哪一个,是什么意思 How long have you been skating?How long did you skate?中文翻译的区别以及语法的区别是什么?