历法是推算年、月、日的时间长度和确定它们之间的关系，制定时间序列的法则。早在古代，由于生产和生活的需要，人们就期待着知道昼夜、月相和季节变化，以及更长时间的计量方法。世界各文明古国也很早就开始根据天象观测来制定历法。万年历在我国应用历史悠久，非常具有民族特色。
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