Xiao Fangzhen, a member of nucleic acid testing support team from Fujian Province, receives an interview in Hong Kong, south China, Sept. 8, 2020. (Xinhua/Li Gang)

Cai Yonglin, a member of nucleic acid testing support team from Guangxi Zhuang Autonomous Region, receives an interview in Hong Kong, south China, Sept. 8, 2020. (Xinhua/Li Gang)

Photo taken on Aug. 26, 2020 shows the Fire Eye Laboratory located at Sun Yat Sen Memorial Park Sports Center in Hong Kong, south China. (Xinhua/Li Gang)

Photo taken on Sept. 8, 2020 shows a poster made by Hong Kong residents to express their gratitude in Hong Kong, south China. (Xinhua/Li Gang)