christmas cards 圣诞贺卡的起源：
the custom of sending christmas cards started in britain in 1840 when the first 'penny post' public postal deliveries began. (helped by the new railway system, the public postal service was the 19th century's communication revolution, just as email is for us today.) as printing methods improved, christmas cards were produced in large numbers from about 1860. they became even more popular in britain when a card could be posted in an unsealed envelope for one half-penny - half the price of an ordinary letter.
圣诞贺卡可追溯到1840年统一便士邮政(uniform penny post)的出现，此项改革实现了英国境内邮件递送费用的标准化。（新铁路运输系统为公共邮政服务系统创造了条件，成就了19世纪的通信革命，与电子邮件对现代人的影响无异）。随着印刷术的改进，从1860年起，每年会生产大量的圣诞贺卡。当邮寄非密封的卡片只要半便士（普通信件邮费的一半）时，邮寄贺卡变得异常流行。
traditionally, christmas cards showed religious pictures - mary, joseph and baby jesus, or other parts of the christmas story. today, pictures are often jokes, winter pictures, father christmas, or romantic scenes of life in past times.
all over britain on christmas day, families can be found sitting around their dining tables enjoying a traditional lunch of roast turkey with all the trimmings - and all, regardless of age, wearing coloured paper hats. it is rumoured that even the queen wears her paper hat over lunch!
so why this quaint tradition? where do these paper hats come from? the answer is the christmas cracker.
a christmas cracker is a cardboard paper tube, wrapped in brightly coloured paper and twisted at both ends. there is a banger inside the cracker, two strips of chemically impregnated paper that react with friction so that when the cracker is pulled apart by two people, the cracker makes a bang.
inside the cracker there is a paper crown made from tissue paper, a motto or joke on a slip of paper and a little gift.
christmas crackers are a british tradition dating back to victorian times when in the early 1850s, london confectioner tom smith started adding a motto to his sugared almond bon-bons which he sold wrapped in a twisted paper package.
the paper hat was added to the cracker in the early 1900s. the cracker was soon adopted as a traditional festive custom and today virtually every household has at least one box of crackers to pull over christmas.