Liu Bang learned the lesson from the demise of the Qin Dynasty, and the Han Dynasty adopted a policy of recuperation. Seeing the disadvantages of land annexation in the Western Han Dynasty, the Eastern Han Dynasty began to restrict this issue. The Tang Dynasty learned the lessons of militarism from the Sui Dynasty and began to admire culture and education. The Song Dynasty learned the lessons from the dictatorship of the big family and consorts in the late Tang Dynasty and adopted the policy of not killing scholars. The Ming dynasty learned the lessons of eunuch intervention in politics in the past, and specially posted a sign at the entrance of the palace, stipulating that eunuchs should not contact politics ... The development of history is precisely to learn the lessons of the past, because it can make people avoid detours. Is to use other people's lessons to enrich their own experience treasure house. Other people's classes are their own free experiences; The wisdom of others can be directly transformed into their own wisdom. The managers of Harley-Davidson motorcycles have a deep understanding of this truth.