All living organisms need metabolism, otherwise life will stop  The same is true of civilization, if it is closed to itself for a long time, it is bound to decline  Exchange and mutual learning is the essential requirement of the development of civilization
Only by communicating with other civilizations and learning from each other's strong points to make up for their weaknesses can we maintain exuberant vitality
If a civilization does not have exchanges and mutual learning with other civilizations, it cannot maintain its exuberant vitality