Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks AIR POLLUTION Air pollution is a cause of ill-health in human beings. In a lot of countries, there are laws limiting the amount of smoke which factories can produce. (19) _______ there isn't enough information on the effects of smoke in the atmosphere, doctors have proved that air pollution (20) _______ lung diseases. The gases from the exhausts of car have also increased air pollution in most cities. The lead in petrol produces a (21) _______ gas which often collects in busy streets surrounded by high buildings. Children (22) _______ live in areas where there is a lot of lead in the atmosphere cannot think as quickly as other children and are clumsy when they use their hands. There are other long-term effects of pollution. If the gases in the atmosphere continue to increase, the earth's climate may become warmer. A lot of the ice near the Pole may melt and may cause serious (23) _______. 1 19.A.However B. Although C. Therefore D. Because 2 20.A. gets B. does C. makes D. causes 3 21.A. dead B. powerful C. poisonous D. harmless 4 22.A. when B. which C. where D. who 5 23.A. flood B. storm C. earthquake D. volcano