People need to breathe. If they don’t breathe, they (1)______ die. But how clean is the air people breathe? If they breathe (2)______ air, they will have breathing problems and become (3)______ . Plants and animals need (4)_____ air too. A lot of the things (5)_____ our lives create harmful gases and (6)______ the air dirty, like cars, motorbikes and factories. Dirty air is called’ (7) ______ air’’. Air pollution can also make our Earth warmer. The problem of air pollution started with the burning (8)_____ coal in homes and factories.

1.

A. will

B. are

C. must

2.

A. clean

B. fresh

C. dirty

3.

A. well

B. better

C. ill

4.

A. clean

B. safe

C. dirty

5.

A. at

B. in

C. on

6.

A. make

B. get

C. give

7.

A. pollute

B. polluted

C. polluting

8.

A. in

B. for

C. of