Paul D. Gewirtz (L), professor & director of China Center of Law School at Yale University, talks with Zheng Yongnian, director of East Asian Institute of National University of Singapore, at the session of "21st Century Maritime Silk Road and Economic Cooperation of the Greater South China Sea" during the Boao Forum for Asia Annual Conference 2018 in Boao, south China's Hainan Province, April 11, 2018. (Xinhua/Guo Cheng)