Đọc kỹ đoạn văn sau rồi chọn phương án (A, B, C hoặc D) để hoàn thành các câu từ 26 đến 30.
Air pollution happens when wastes dirty the air. People reduce most of the wastes that cause air pollution. Such wastes can be in the form of gases or particles of solid or liquid matter. These substances result chiefly from burning fuel to power motor vehicles and to heating buildings. Industrial processes and the burning of garbage also contribute to air pollution. Besides, there are other substances that naturally exist in the air. They include dust, pollen, soil particles, and naturally occurring gases.
The rapid growth of population and industry and the increasing use of automobiles and airplanes have made air pollutionn a serious problem. The air we breathe has become so filled with pollutants that can cause health problems. It also harms plants, animals, building materials, and fabrics
What does NOT contribute to air pollution?
A.Industrial processes
B.The natural existence of oxygen in the air
C.The burning of garbage
D.Motor vehicles