Chinese President Xi Jinping, also general secretary of the Communist Party of China Central Committee and chairman of the Central Military Commission, visits a research institute of the Ocean University of China to learn about the development of marine science and technology in Sanya, south China's Hainan Province, April 10, 2022. Xi on Sunday inspected the city of Sanya, south China's Hainan Province. (Xinhua/Yan Yan)