英语,【Do you have an appointment?】问的是发生过的事情,为什么不用【Did】?

英语,【Do you have an appointment?】问的是发生过的事情,为什么不用【Did】? Do you have an appointment里面的an是什么意思. DO you have an appointment Do you have an appointment?为什么要用do啊 英语句子 你收到我的信了吗,用do you received 还是 did you ,或者是 have you 为什么? hello,may i have an appointment with the headmaster?为什么不用sor Have you made an appointment ( ) the doctor? Did you marry/Have you married为什么是错的 Did he have a key?这里的he是第三人称,为什么不用has而用have? He did it as if he were an expert.从句表示的动作发生在过去,为什么不用过去完成时 英语：what did you do 为啥后面的就不用变过去式了呢? Do you have some fish?Sorry,we don't have here.为什么用some,不用an