第一个计算有关人类的劳动与休息相互更替的时间单位是昼夜。所谓昼夜是指两个中午或两个午夜之间的时间,也就是地球绕自己的轴心自转一周的时间。后来还出现了太阳月或朔望月,也就是指两次新月之间的时间。最早,朔望月定为三十天,后来确定为二十九点五个昼夜。与月球运转有关的还有另外一个计量单位,即七日制周。月历起于古老的游牧民族。随着人们逐渐定居下来,就需要确定播种和收割庄稼的日期。这些日期是与一年四季的更替,即与太阳的运动密切相关 The first unit of time to calculate the mutual replacement of labor and rest for human beings is day and night. The so-called diurnal refers to the time between two noon or two midnight, that is, the Earth’s axis of rotation around a week’s time. Later, the moon or moon appeared, which means the time between two new crescent moon. The earliest, lunar new moon for thirty days, and later identified as twenty-nine five days and nights. There is another unit of measurement related to the operation of the moon, namely the seven-day week. Calendar from the ancient nomad. As people settle down, the dates of planting and harvesting of crops need to be determined. These dates are alternations throughout the year, and are closely related to the movement of the sun