All living organisms need metabolism, otherwise life will stop. The same is true of civilization, if long-term self-closure, it will definitely decline. Exchanges and mutual learning are essential requirements for the development of civilization. Only by communicating with other civilizations and learning from each other's strengths can we maintain a strong vitality. From this we can deduce? ['If a civilization does not communicate with other civilizations and learn from each other, it cannot maintain its vitality.', 'A civilization will not decline if it is not closed for a long time.', "If a civilization communicates with other civilizations and learns from each other's strengths, it can maintain its vitality and vitality.", 'If a civilization does not maintain strong vitality, it will not learn from other civilizations.']