[单项选择]As America’’s air becomes steadily more contaminated, activities across the nation to cope with smog appear to be lagging further and further behind actual needs despite a rising public clamor for improvement. 　　 There has been a considerable progress in the last couple of years. But the over-all picture is that so many localities haven’’t really come to grips with the air pollution problem that people might be dismayed if they knew how their welfare was being trifled with. 　　Air pollution sources are now hurling more than 140 million tons of contaminants into the atmosphere every year, by Federal estimates. Two years ago it was only 130 million tons. 　　The increase has been caused by many things--more people, more automobiles, more industry, more space heating, little if any reduction that more often than not are inadequate. 　　The adverse health effects of air pollution are becoming more widely recognized, although specific medical evidence is still fragmentary. As a psychological
A. many local authorities haven’’t grasped the essence of pollution.
B. a lot of people haven’’t started to deal seriously with the problem.
C. a number of places haven’’t located the sources of contamination.
D. few health organizations have realized its disastrous consequences.