Christmas Eve前面是用at还是on

Christmas Eve前面是用at还是on christmas eve前面究竟加介词at 还是 on? at Christmas eve or on Christmas eve ___ Christmas eve填on in 还是at Christmas Eve前加in at to还是on at christmas on Christmas Eve对吗? Christmas Eve前面用什么? 是on Christmas还是at Christmas? at eve还是on eve christmas eve是用merry还是HAPPY? on christmas 还是at christmas at christmas和on christmas eve推广之后是什么?