April Fool's Day或All Fools' Day。
愚人节也称万愚节、幽默节，愚人节。
节日时间：公历4月1日。是从19世纪开始在西方兴起流行的民间节日，现在并未被任何国家认定为法定节日。
节日内容：在这一天人们以各种方式互相欺骗和捉弄，往往在玩笑的最后才揭穿并宣告捉弄对象为“愚人”。
玩笑的性质极少包含实质恶意，但个别玩笑由于开得过大而引起人们的恐慌，从而产生较大规模反响并且衍生成为（传媒）谣言和都市传说，所以对于人们来说一般会加以避免开如有关灾难之事的玩笑。
注意事项：愚人节这天玩笑只能开到中午12点之前，这是约定俗成的严格规定，过了钟点还开玩笑的人会自找没趣儿。
愚人节用英语表达为April Fool's day.
相传距人类始祖亚当之后约一千六百五十年间，上帝以洪水来毁灭世界，但仅留下亚当的第三个儿子慧德的后代诺亚，他以一条人造的大船保全了一家大小的生命。
According to legend, about 1650 years after Adam, the first human ancestor, God destroyed the world by flood, but only Noah, the descendant of Huide, Adam's third son, was left. He saved the life of his family by a man-made ship.
洪水稍退之后，诺亚便放出一只白鸽，想探求一块洪水消退之后的陆地，因为这一天正好是四月一日。
When the flood subsided, Noah released a dove to explore a piece of land after the flood subsided, because it happened to be April 1.
所以后人认为，在这一天去做一种毫无意义的事，就好像一只白鸽做了白工一样，行为愚蠢，为“愚人节”之起源。
Therefore, later generations think that to do a meaningless thing on this day is like a white dove doing a white job. It's stupid, which is the origin of April Fool's day.
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