The principle of keeping in good health: conforming to nature and keeping in good health in harmony with nature is also the "method of yin and yang, the sum of skills" of traditional Chinese medicine; When you do things, you are naturally smooth. You can make good use of limited things and maximize the benefits of contacts without hurting them. This is a very high realm of doing things, which can be said by Confucius as "walking at seventy, not exceeding the moment."