原文:
       What, exactly, are the 12 days of Christmas?
       The 12 days of Christmas are the 12 days that separate Christmas day on December 25 from Epiphany, which is celebrated January 6. Depending on the church, January 6 may mark Christ's baptism (the Catholic tradition), or it may mark the day that the wise men visited the baby Jesus with their gifts. 

       In the past, there was a tradition of giving gifts throughout the 12 days, rather than stacking them all up on the morning of December 25. That tradition, as you might imagine, has never really caught on in America! We just aren't that patient. The song, however, demonstrates that some people once stretched out their gifts (and gave some fairly elaborate gifts...) over the full 12 days. 

       Drennon's Twelve Days of Christmas offers some interesting perspectives on the 12 days of Christmas and the song of that same title. This page also contains a thesis full of information!

译文:
        确切的圣诞节的十二天是什么?
        圣诞节的十二天是从主显节中分离出十二月二十五号圣诞节的十二天,主显节是在一月六号欢庆.在一月六号的主显节里也许会依托教堂进行圣主的洗礼(天主教的传统仪式),或者明智的人们会在这一天带着礼物礼拜圣子耶酥.

       过去人们有贯穿在这十二天内赠送礼物的传统,而不是在十二月二十五号清晨把礼物都堆起来,你可能在想象的老传统,在美国从来没有真的流行过!不过我们得耐心点,无论如何歌曲证明了人们曾经在整十二天内伸手拿过礼物(同时也回赠了相当精心制作的礼物).

       Drennon的十二天圣诞节对圣诞节的十二天和同一题目的歌曲提出了一些有意思的看法,这个专栏也包含了一个有详尽资料的论点.