Spaniard Eva Serrano quickly mustered eight colleagues to work as community volunteers after she heard about "\\;grid screening"\\; in her community."\\;Grid screening"\\; is a strategic pattern in the massive round of nucleic acid testing among local citizens launched by the city's government. It aims to curb the spread of the virus in affected areas with a higher risk of infection, where residents will be quarantined and complete two nucleic acid tests within 48 hours.When it was the turn of her community on Yuyuan Road in Jing'an District, she didn't hesitate to step up.