Trading is one of the most basic activities of mankind.It has existed in every society, every part of the world, and in fact every day since the caveman came into being.

• 贸易是人类最为基本的活动之一，每个社会都有贸易活动，并存在于世界各地，事实上，从洞穴人开始就已经有了贸易交往活动。