the first morning,the first day前面加不加on,还是都可以

the first morning,the first day前面加不加on,还是都可以 On the first day 还是 on first day 如果加一个morning呢? 应该说on the first day还是at the first day on the first day还是in the first day on the first day还是in the first day还是at the first? on the first day morning有语法错误吗? on the very first day in the first day of my life 还是on the first day of my life “在第一天”是on the first day还是in the first day 有没有in the first day,on the first day in the first day on the first day区别 ON the morning of March first.可以这样翻译吗?on the morning on marc