According to the definition of Beijing and the standard implemented in many areas of China, it is to stay with the confirmed person for more than 10 minutes within a range of 800 by 800 meters. Or, in the last 14 days, if you have stayed in the same place for more than 30 hours with either of the confirmed patients, you will win the lottery. The basis for tracing is your mobile phone.
Because the positioning signal of the mobile popular database phone can be fully grasped by the base station, and this is the strength of the Chinese government. Under such a powerful "space-time connection", it is not only the "space-time attendants" and "space-time coincidences" who are impacted. Others who are related to those who are accompanied and implicated will also be affected. Li Fang (pseudonym), who teaches at an academy in Beijing, is the one who was affected for no reason.
It turned out that the three female students in Li Fang's class were listed as "time-space overlap" objects because they shopped at the same shopping mall with a confirmed patient in Changping District, Beijing at the same time. At the request of the epidemic prevention unit, in addition to the three female students who were quarantined at home for 14 days, other students must also be observed at home for 14 days, resulting in the suspension of the whole class for up to 2 weeks.