I know: catch sand to make mercury, replace trees with flowers, know what life is like, ask.

Making mercury from sand is a Taoist term, which refers to the practice of alchemy inside and outside. Inner Dan refers to the practice of refining air conditioning to adapt to the internal air. External alchemy refers to refining external alchemy with lead, mercury and other substances for a person with fixed practice to take and grow up. Grafting refers to modern grafting technology, and also refers to pumping oil to extend life. There are several explanations, but I don't know which one you want to know As for the last one, it refers to a high level of practice of Buddhism, Taoism and Confucianism, which is also called understanding nature. It means understanding the essence of life, the laws of the universe, being independent of one's own destiny, transcending reincarnation and reaching the state of becoming immortal and Buddha.