Opinion polls repeatedly tell us that the only thing Americans worry about more than the environment is their health. This is【B1】understandable, for health is obviously【B2】to illness. What makes today's concern【B3】health slightly surprising is that Americans are【B4】healthier now than they. have ever been. Many diseases that once【B5】terror into hearts have either been completely【B6】or brought under control. Although AIDS is a notable【B7】, few new mass killers have come out to【B8】the ones that have been eliminated.【B9】, health—and the various threats to it—remains everyone's【B10】concern. After all, more than half of us(57 percent) will die from either heart disease or cancer, if current【B11】continues. One major problem with any【B12】of health risks—especially life-threatening ones is that they【B13】enormously in their immediacy. For instance, AIDS If you get it—will probably be【B14】after a number of years. Cancer induced by smoking or【B15】to radiation, on the other hand, may take 20 to 30 years【B16】its fatal effects show【B17】. In making choices about health risks,【B18】, it is important to bear in【B19】the likely time lag between taking a risk and【B20】its consequences. 【B1】