【正确答案】According to the Chinese ancient historical records, the legendary leader Shun abdicated and handed over his leadership to Da Yu who had made great contribution to controlling the flood of the Yellow River of China. When Da Yu died, his son Xia Qi breached the tradition of demise system and set himself as the king. Xia, the first slavery nation in Chinese history, was founded. Since then, the hereditary system had been practiced. Thus, China stepped into a class society. The Xia Dynasty was a transition from primitive society to slave society. At that time, all aspects of social life still preserved traces of primitive society.