单选题 《复合题被拆开情况》 There is no doubt that air pollution is a global crisis: it causes an annual death【C1】______of 6.5 million. That is double the total number of people lost【C2】______HIV/AIDS, tuberculosis and malaria【C3】______, and four times the number killed on the world’s roads. Half the early deaths result from outdoor air pollution that is far more dispersed and harder to【C4】______. Air pollution has increased the【C5】______of mental illness, diabetes and kidney disease. It is even thought to be prematurely ageing the faces of city dwellers by accelerating wrinkles and age【C6】______. What’s worse, almost 90% of the world’s children live where outdoor air pollution【C7】______WHO limits. Increasing efforts【C8】______global warming by cutting the fossil fuel consumption will help cut air pollution. Some major world cities are also doing something【C9】______traffic smog by setting dates【C10】______the worst polluting cars will be banned. The huge cuts in health costs that could be achieved with cleaner air are becoming better understood.《问题》：【C4】