愚人节，为什么是4月1日？

April Fools Day is on April 1. 愚人节就在4月1日。 People play light jokes on that day. 这一天，大家会开轻松的玩笑。 One old story is about the new calendar. 有个老说法，和历法改革有关。 Some people still used the old new year. 有些人还按旧历法过新年。 Others laughed at them. 其他人就会笑话他们。 Those people became April fools. 这些人就成了四月愚人。 Just keep the jokes kind and gentle. 开玩笑要把握分寸，别伤人。