Professor, dean and doctoral supervisor at the School of Chinese as a Second Language, Peking University.
Ph.D. from Cambridge University. His research interests include second language acquisition, generative grammar, sociolinguistics, and language education. He serves as vice president of the International Society for Chinese Language Teaching (ISCLT), chairman of the ISCLT Standards and Certification Committee, chairman of the Special Committee for International Chinese Education and Language Exchange at the Academic Alliance of International Cultural Exchange, vice president of the Second Language Acquisition Research Committee of the China Association for Comparative Studies of English and Chinese (CACSEC), member of the Education Guidance Committee of the National Chinese International Education Degree, and editor-in-chief of the International Chinese Language Education journal.