Knowledge classification and the reconstruction of China's modern academic system 并列题名：Knowledge classification and the reconstruction of China's modern academic system Aging of the population and the construction of the elderly service system Research on the construction of the capital's modern economic system 并列题名：Research on the construction of the capital's modern economic system Innovation of higher education and the construction of lts management system RMB universalization and the construction of world digital monetary system Internet of everything and the construction of enterprise ecosystem