单选题 　第三篇 　Exercise Lowers Employers‘Health Costs 　　Companies can save millions in health-care costs simply by encouraging their employees to exercise a little bit，researchers reported on Friday 　　They said obese(肥胖的)employees had higher health。care costs，but lowered those expenses by exercising just a couple of times a week——without even losing any weight. 　　Feifei Wang and colleagues at the University of Michigan studied 23，500 workers at General Motors． 　　They estimated that getting the most sedentary(惯于久坐的)obese workers to exercise would have saved about$790,000 a year．or about 15 percent of health—care costs for the whole group Company—wide，the potential savings could reach$7.1 million per year，they reposed in the Journal of Occupational and Environmental Medicine． 　　Of the whole group of workers，about 30 percent were of normal weight，45 percent were overweight(超重的)，and 25 percent were obese．Annual health—care costs averaged$2，200 for normal weight，$2,400 for the overweight，and$2,700 for obese employees． 　　But among workers who did no exercise，healthcare costs went up by at least $100 a year，and were$3,000 a year for obese employees who were sedentary． 　　But adding two or more days of light exercise——at least 20 minutes of exercise or work hard enough to increase heart rate and breathing——lowered costs by on average$500 per employee a year，the researchers found．

单选题 How can employees help lower the health—care costs?

单选题 By encouraging its employees to exercise General Motors could save

单选题 How many workers in General Motors were NOT of normal weight?

单选题 For which group of the workers were the health—care costs the highest?

单选题 How often should the employees exercise to help lower the health-care costs?