Christmas Eve前加in at to还是on

Christmas Eve前加in at to还是on christmas eve前面究竟加介词at 还是 on? ___ Christmas eve填on in 还是at at Christmas eve or on Christmas eve 为什么Christmas 前加at,Christmas day前加on We shall have a feast< >Christmas Eve.A to B on C at D in Christmas Eve前面是用at还是on at christmas on Christmas Eve对吗? at eve还是on eve on christmas 还是at christmas 在具体时间前加on还是in还是at? the summer 前加on还是in还是at