Candidates prepare to sit the national postgraduate entrance exam at Nanjing Forestry University in Nanjing, east China's Jiangsu Province, Dec. 21, 2019. More than 3.4 million Chinese have signed up for the 2020 national exam for postgraduate enrolment scheduled from Dec. 21 to 23, the Ministry of Education said. (Photo by Liu Jianhua/Xinhua)

Candidates take the national postgraduate entrance exam at University of South China in Hengyang, central China's Hunan Province, Dec. 21, 2019. More than 3.4 million Chinese have signed up for the 2020 national exam for postgraduate enrolment scheduled from Dec. 21 to 23, the Ministry of Education said. (Photo by Cao Zhengping/Xinhua)

Candidates prepare to sit the national postgraduate entrance exam at University of South China in Hengyang, central China's Hunan Province, Dec. 21, 2019. More than 3.4 million Chinese have signed up for the 2020 national exam for postgraduate enrolment scheduled from Dec. 21 to 23, the Ministry of Education said. (Photo by Cao Zhengping/Xinhua)

A student walks outside the exam rooms for the national postgraduate entrance exam at University of South China in Hengyang, central China's Hunan Province, Dec. 21, 2019. More than 3.4 million Chinese have signed up for the 2020 national exam for postgraduate enrolment scheduled from Dec. 21 to 23, the Ministry of Education said. (Photo by Cao Zhengping/Xinhua)