单项选择题

It’’s hardly news anymore that Americans are just too fat. A quick look around the mall, the beach or the crowd at any baseball game will leave no room for doubt:our individual weight problems have become a national crisis. Even so, the actual numbers are shocking. Fully two-thirds of U. S. adults are officially overweight, and about half of those have graduated to full-blown obesity.   It wouldn’’t be such a big deal if the problem were simple aesthetic. But excess poundage takes a terrible toll on the human body. significantly increasing the risk of heart disease, high blood pressure, diabetes, infertility, and many forms of cancer. The total medical bill for illnesses related to obesity is $117 billion a year-and climbing - and the Journal of the American Medical Association reported that poor diet and physical inactivity could soon overtake tobacco as the leading cause of preventable death in the U. S.   Why is it happening The obvious, almost trivial answer is that we eat too much high-calorie food and don’’t burn it off with enough exercise. If only we could change those habits, the problem would go away. But clearly it isn’’t that easy. Americans pour scores of billions of dollars every year into weight-loss products and health-club memberships. Food and drug companies spend even more trying to find a magic food or drug that will melt the pounds away. Yet the nation’’s collective waistline just keeps growing.   It’’s natural to try to find something to blame - fast-food joints or food manufacturers or even ourselves for having too little willpower. But the ultimate reason for obesity may be rooted deep within our genes. Obedient to the inevitable laws of evolution, the human race adapted over millions of years to living in a world of scarcity, where it paid to eat every good-tasting thing in sight when you could find it.   Although our physiology has stayed pretty much the same for the past 50,000 years or so,we humans have utterly transformed our environment. Over the past century especially, technology has almost completely removed physical exercise from the day-to-day lives of most Americans. At the same time, it has filled supermarket shelves with cheap, mass-produced, good-tasting food that is packed with calories. And finally, technology has allowed advertisers to deliver constant, virtually irresistible messages that say "Eat this now" to everyone old enough to watch TV.   This artificial environment is most pervasive in the U. S. and other industrialized countries, and that’’s exactly where the fat crisis is most acute. The text arranges obesity according to

A. class.
B. size.
C. grade.
D. rank.
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填空题
The differences in relative growth of various areas of scientific research have several causes. 71. Some of these causes are completely reasonable results of social needs. Others are reasonable consequences of particular advances in science being to some extent self-accelerating. Some, however, are less reasonable processes of different growth in which preconceptions of the form scientific theory ought to take, by persons in authority, act to alter the growth pattern of different areas. This is a new problem probably not yet unavoidable; but it is a frightening trend. 72.This trend began during the Second World War, when several governments came to the conclusion that the specific demands that a government wants to make of its scientific establishment cannot generally be foreseen in detail. It can be predicted, however, that from time to time questions will arise which will require specific scientific answers. It is therefore generally valuable to treat the scientific establishment as a resource or machine to be kept in functional order. 73. This seems mostly effectively done by supporting a certain amount of research not related to immediate goals but of possible consequence in the future.This kind of support, like all government support, requires decisions about the appropriate recipients of funds. Decisions based on utility as opposed to lack of utility are straightforward. But a decision among projects none of which has immediate utility is more difficult. The goal of the supporting agencies is the praisable one of supporting good as opposed to bad science, but a valid determination is difficult to make. Generally, the idea of good science tends to become confused with the capacity of the field in question to generate an elegant theory. 74. However, the world is so made that elegant systems are in principle unable to deal with some of the world’’s more fascinating and delightful aspects. 75. New forms of thought as well as new subjects for thought must arise in the future as they have in the past, giving rise to new standards of elegance.