If you have been to a high-risk area or passed through a high-risk area and stayed for 4 hours, our health code may change and turn yellow or even red. Followed by the most popular time and space companionship on the Internet. If we are accompanied by time and space, our health code will turn yellow. If you don't go to high-risk areas, don't contact with confirmed cases, and send things to people in middle-risk areas, the health code will not turn yellow.