摘要
AT 8:30 a.m.,Chegongzhuang metro station is one of the busiest transportation hubs in Xicheng District,Beijing.Commuters line up in an orderly manner to go through the security check,get temperatures screened,swipe metro cards,and then enter through the turnstiles.Many commuters now also use their smartphones to enter by swiping the screen over the sensor on the turnstile.
