https://online2.tingclass.net/lesson/shi0529/0001/1112/tingclass_4663xdh.mp3
https://image.tingclass.net/statics/js/2012
W: Why do you wear a mask?
M: The air is too dirty, especially in the streets.
W: I have the same feeling.
M: Everyday when I wash my face, I find the water turns black.
W: But I don't like wearing a mask, and it's not the effective way to solve the problem.
M: I know. But what can we do? We have to go to school by bike.