Alex: Hi, David. How was your football match? David: Oh, it couldn’t have been worse! It was because of the heavy . Alex: That’s too bad. When the is not good, I always wear a . David: Yeah, but I don’t like wearing a mask. It would be funny to wear a mask while playing football. Alex: (laughing) You’re right. David: I hope the government can do something to improve the air quality. Alex: Actually, they’ve already done a lot in improving the air quality and dealing with other , but I think the most important thing is everyone’s . Our planet doesn’t need . It needs action. David: Yeah, I agree with you. We must in protecting the environment.