Teacher Chen Weiwen interacts with her students during a trial online class in Shanghai, east China, February 25, 2020. Students in Shanghai attended a trial online class on Tuesday, a rehearsal for the online tuition scheduled to start on March 2. [Xinhua/Liu Ying]

Teacher Chen Weiwen interacts with her students during a trial online class in Shanghai, east China, February 25, 2020. Students in Shanghai attended a trial online class on Tuesday, a rehearsal for the online tuition scheduled to start on March 2. [Xinhua/Liu Ying]

Teacher Chen Weiwen interacts with her students during a trial online class in Shanghai, east China, February 25, 2020. Students in Shanghai attended a trial online class on Tuesday, a rehearsal for the online tuition scheduled to start on March 2. [Xinhua/Liu Ying]

Teacher Chen Weiwen interacts with her students during a trial online class in Shanghai, east China, February 25, 2020. Students in Shanghai attended a trial online class on Tuesday, a rehearsal for the online tuition scheduled to start on March 2. [Xinhua/Liu Ying]

(Source: Xinhua)