a day与one day 区别

a day与one day 区别 one day,some day,other day,a day,的区别 the day,one day,a day,on day的区别 some day 与one day 的区别 some day 与 one day的区别? one day a day 区别 谢谢 one day和a day什么区别 some day,a day和one day的区别 one day some day 区别 a day与 one day 都可作状语么 有什么区别 a day or two 与 one day or two 的区别? on such a day 与on one such day 有什么区别?