Ning Guan and Hua Xin were hoeing vegetables in the garden when they saw a piece of gold on the ground. Guan Ning keeps hoeing the ground, which is tantamount to seeing a stone. Huaxin picked up the gold and threw it away. They used to sit at the same table and study. An official in a limousine passed by the door. Guan Ning still studied as before, but Huaxin put down his book and went out to read it. Ning Guan cut the mat and sat down separately, saying, "You are no longer my friend."

2. The awkward turning point and differences between Zhang Er and Chen Yu:

Zhang Er and Chen Yu are both famous. Chen Yu's great-grandfather was Zhang Er, and Zhang Er prevented Chen Yu from killing a small official on impulse, thus saving Chen Yu's life in disguise. The latter two defected, slightly defected to Zhao, and became the king of Zhao.