— Air quality in our city is becoming worse and worse.—Yes. These days' PM2.5 readings are frightening. We must do something to ______air pollution.

题型：单选题题类：常考题难易度：普通

— Air quality in our city is becoming worse and worse.
—Yes. These days' PM2.5 readings are frightening. We must do something to ______air pollution.

A、reduce B、remove C、collect D、gather