Why Doctors Wear Masks
(Originally in English)
Once a small child asked his father, "Father, why do
doctors always have to wear masks in the operating
room?" And the father replied, "In case something
goes wrong, no one will know who they are." 

医生为什么戴口罩？

小孩问他的父亲：‘爸爸，为什么医生在手术房
里面都要戴口罩？’父亲说：‘怕万一发生什么
事的话，就没有人知道他们是谁！’