Chose a, b, c or d to complete the following passage.
People need to breath. If they don't breath, they (1)............... die. But how clean is the air people breath? If they breath dirty air, they will have breathing problems and (2)................ ill. Plants and animals need clean air, too (3).................. of things in our lives create harmful gases and make the air dirty, like cars, motorbike and factories. Dirty air called (4)................... air. Air pollution can also makes our Earth warmer. The problem of air pollution started (5).................. the burning a lot of coal in homes and factories.
1-A. will B. is C. are D. won't
2-A. become B. became C. becomes D. will become
3-A. some B. many C. few D. a lot
4-A. pollute B. polluted C. pollution D. polluting
5-A. with B. of C. at D. on