整个社会的发展如同一条机械加工生产线一般，只能不断的向前。而社会上的每一个人便是这条生产线上不同的工具，有着不同的属性、作用。如果你坏掉了，便会换上新的工具，从不会因为你的缺席而停止运转。 The development of the society as a mechanical processing production line, only forward. And everyone in the society is the different tools on the production line, have different properties, function. If you is broken, we can change into new tools, the production line will not stop because of your absence.