1. China's closed-door policy leads to backwardness, in contrast to the rapid development of Europe's active opening to the world.
2. Xu Xiake wrote "Xu Xiake's Travels" because he actively went out to explore nature, enjoyed the great rivers and mountains of the motherland, and made outstanding contributions to the geographical cause of China.
Li Shizhen wrote Compendium of Materia Medica because he was not satisfied with book knowledge when he left home through practice, which laid the foundation for medical career at home and abroad.
Because Tang Xuanzang walked out of Buddhism, he taught Buddhist knowledge to all parts of the world and freed more people from suffering.
In other words, we can write about the importance of practice by writing doors, and actively encourage people to bravely go out and practice hard.