I. Choose the correct answer A, B, C or D to complete the passage. (1.0m) 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. Plants and animals need (3) __________ air too. A lot of the things in our lives create harmful gases and (4) _________the air dirty, like cars, motorbikes, and factories. Dirty air is called polluted air. Air pollution can also make our Earth warmer. 1. A. must B. are C. will D. won’t 2. A. fresh B. clean C. cleaner D. dirty 3. A. clean B. safe C. dirty D. polluted 4. A. get B. make C. give D. made