first和first one区别 请高人帮帮忙

first和first one区别 请高人帮帮忙 the one 和the first的区别 First和one的区别Her twenty-first birthday is in 1999.first可以换成one吗? number one 和 the first 有什么区别 the first one to do和the first to do的区别 first 和 at first 的区别 on first和first的区别 the first和first有什么区别 first和at first的区别? first 和the first 有什么区别 At first 和first 有什么区别? first trial 和first instence 的区别? first one first和the first的区别.请顺便讲讲序数词前有无定冠词的区别, first和at first 有什么区别?怎么区别什么时候用first,什么时候用at first? for the first time 和 the first time的区别,请详解 once,one,first有什么区别 first step和first