1. School of Information Science and Technology, Guangdong University of Foreign Studies, Guangzhou, People’s Republic of China
2. Guangzhou Key Laboratory of Multilingual Intelligent Processing, Guangdong University of Foreign Studies, Guangzhou, People’s Republic of China
3. School of Computer, Guangdong University of Technology, Guangzhou, People’s Republic of China
4. Laboratory of Language Engineering and Computing, Guangdong University of Foreign Studies, Guangzhou, People’s Republic of China