[简答题]For years, the prescription for maintaining health hearts had been vigorous exercise—running, swimming, dancing—whatever it took to get the heat rate up and keep it there for 20 to 30 minutes at least three times a week. But that message changed.
A panel of exercise researchers convened by the Centers for Disease Control and Prevention and the American College of Sports Medicine reported that people needn’t exercise vigorously to improve their health.
The American Heart Association has weighed in with similar recommendations. But despite this apparent consensus, there is considerable disagreement in the exercise research community about whether the recommendations are amply supported by scientific data.
Policy-makers caught in the middle of this disagreement are in a difficult position. It’s a classic dilemma confronting health experts in areas ranging from mammography (哺乳动物学) to diet, where the scientific data are not clear-cut.

[填空题] Maintaining body health is one of the most important tasks in life. A healthy body requires (36)______foods and liquids for growth, development , and (37)______ against disease. A healthy body also (28 )______fresh air, exercise, and rest. Maintaining body health requires (39)______effort. You choose the foods you eat. You choose (40)______you get fresh air and exercise. You choose how much rest you get. Nutrition is one of the most important (41)______of body health. When people do not eat enough food or do not take in certain (42)______ nutrients, they can suffer from (43)______. Sometimes disease robs the body of the essential nutrients in the diet. This condition is called secondary malnutrition. (44)____________. Three essential substances which may come from foods are carbohydrates, fats, and proteins. Carbohydrates provide body fuel. Fats are stored in the body for future energy uses. Proteins are required for growth needs and for defending the body agains

[填空题]For years, mental health professionals were trained to see children as mere products of their environment that were born good until influenced otherwise; where there is constant bad behavior, there must be a bad parent behind it.
But while I do not mean to let bad parents off the hook, the fact remains that perfectly decent parents can (36) toxic (有毒的) children. When I say "toxic," I don’t mean psychopathic (精神变态的)—those children who (37) into petty criminals (小混混), killers and everything in between.
One of my patients told me about his son, now 35, who despite his many (38) was short-tempered and rude to his parents—refusing to return their phone calls and e-mails, even when his mother was (39) ill. He told me, "We have racked our (40) trying to figure why our son treats us this way. We don’t know what we did to (41) this." Apparently very little, as far as I could tell.
We marvel at the spirited ch