楼上说的不全面,如：i think that you are a good student.don't you?
he said that you are a good student,didn't you?
the girl who is over there is my sister,isn't she?
由上可见,定语从句根据主句来作反意疑问句,宾语从句,如果引导词是think purpose believe等,看从句,其它的一般用don't +主语（注意时态）.