1. School of Educational Technology, Faculty of Education, Beijing Normal University, Beijing, People’s Republic of China
2. Department of Foreign Languages, Beijing University of Posts and Telecommunications, Beijing, People’s Republic of China
3. National Taiwan Normal University, Taipei, Taiwan
4. Shandong Normal University, Jinan, People’s Republic of China
5. National Engineering Research Center for E-Learning, Central China Normal University, Wuhan, People’s Republic of China