Liao Yalong (front) and Li Zhengkang, both members of a team of seven virus testing professionals, set out from southern China's Guangdong Provincial People's Hospital to Hong Kong for assistance in COVID-19 fight, in Guangzhou, south China's Guangdong, Aug. 2, 2020. Seven virus testing professionals from the Chinese mainland arrived in Hong Kong on Sunday afternoon as the first batch of mainland supportive teams to help contain a worsening spread of COVID-19 in Hong Kong. (Xinhua/Deng Hua)