on christmas 和at holiday区别

on christmas 是在圣诞节的意思，而at holiday则是在假期的意思，区别可以从以下例子看到

I know you are at holiday, but We are very busy on christmas, please come back to save us. I know i own you. 知道你在放假，但我们圣诞节很忙，请回来救我们。我知道我欠你了。