单选题
How exercise affects body weight is one of the more intriguing and vexing issues in physiology. Exercise burns calories, no one doubts that, and so it should, in theory, produce weight loss, a fact that has prompted countless people to undertake exercise programs to shed pounds. Without significantly changing their diets, few succeed. "Anecdotally, all of us have been cornered by people claiming to have spent hours each week walking. running, stair-stepping, etc., and are displeased with the results on the scale or in the mirror, "wrote Barry Braun. an associate professor of kinesiology at the University of Massachusetts at Amherst. But a growing body of science suggests that exercise does have an important role in weight loss. That role, however, is different from what many people expect and probably wish. The newest science suggests that exercise alone will not make you thin, but it may determine whether you stay thin, if you can achieve that state. Until recently, the bodily mechanisms involved were mysterious. But scientists are slowly teasing out exercise's impact on metabolism, appetite and body composition , though the consequences of exercise can vary. Women's bodies, for instance, seem to react differently than men's bodies to the metabolic effects of exercise. None of which is a reason to abandon exercise as a weight-loss tool. You just have to understand what exercise can and cannot do. "In general, exercise by itself is pretty useless for weight loss, "says Eric Ravussin, an expert on weight loss. It's especially useless because people often end up consuming more calories when they exercise. The mathematics of weight loss is, in fact, quite simple, involving only subtraction. "Take in fewer calories than you burn, put yourself in negative energy balance, lose weight, "says Braun, who has been studying exercise and weight loss for years. The deficit in calories can result from cutting back your food intake or from increasing your energy output — the amount of exercise you complete — or both. When researchers affiliated with the Pennington center had volunteers reduce their energy balance for a study by either cutting their calorie intakes by 25 percent or increasing their daily exercise by 12.5 percent and cutting their calories by 12.5 percent, everyone involved lost weight. They all lost about the same amount of weight too — about a pound a week. But in the exercising group, the dose of exercise required was nearly an hour a day of moderate-intensity activity. What the federal government currently recommends for weight loss is "a lot more than what many people would be able or willing to do," Ravussin says. At the same time, as many people have found after starting a new exercise regimen, working out can have a significant effect on appetite. The mechanisms that control appetite and energy balance in the human body are elegantly calibrated. "The body aims for homeostasis, " Braun says. It likes to remain at whatever weight it's used to. So even small changes in energy balance can produce rapid changes in certain hormones associated with appetite, particularly acylated ghrelin, which is known to increase the desire for food, as well as insulin and leptin, hormones that affect how the body burns fuel. The effects of exercise on the appetite and energy systems, however, are by no means consistent. In one study presented last year at the annual conference of the American College of Sports Medicine, when healthy young men ran for an hour and a half on a treadmill at a fairly high intensity, their blood concentrations of acylated ghrelin fell, and food held little appeal for the rest of that day. Exercise blunted their appetites. A study that Braun oversaw had a slightly different outcome. In it, 18 overweight men and women walked on treadmills in multiple sessions while either eating enough that day to replace the calories burned during exercise or not. Afterward, the men displayed little or no changes in their energy-regulating hormones or their appetites, much as in the other study. But the women uniformly had increased blood concentrations of acylated ghrelin and decreased concentrations of insulin after the sessions in which they had eaten less than they had burned. Their bodies were directing them to replace the lost calories. In physiological terms, the results "are consistent with the paradigm that mechanisms to maintain body fat are more effective in women, "Braun and his colleagues wrote. In practical terms, the results are scientific proof that life is unfair. Female bodies, inspired almost certainly" by a biological need to maintain energy stores for reproduction, "Braun says, fight hard to hold on to every ounce of fat. Exercise for many women increases the desire to eat.
单选题
We can infer from the text that [A] going on diet will definitely lead to weight loss. [B] the theory of exercise burning calories is challenged. [C] it is often disappointing to lose weight by doing exercise. [D] most people tend to spend hours walking, running, etc.
【正确答案】
C
【答案解析】推断题。根据题目顺序从首段开始浏览，在首句提出“how exercise affects body weight”这一主题之后，第三句指出结果“Without significantly changing their diets, few succeed”，之后引用Barry Braun的活做进一步说明“Anecdotally, all of us have been cornered by people claiming to have spent hours each week walking，running, stair-stepping, etc. , and are displeased with the results on the scale or in the mirror”，可见，多数人都无法通过锻炼达到减肥的目的，让人失望是必然的结果，故[C]为答案。 [避错] [A]中的definitely表明该项为绝对项，直接排除；第二句明确指出“Exercise burns calories, no one doubts that”，[B]项与之矛盾，排除；而末句中的“people claiming to have spent hours each week walking, running, stair-stepping, etc.”是指那些想通过锻炼减肥的人，并非most people。排除[D]。
单选题
The phrase "teasing out" in Paragraph 2 probably means succeeding in [A] testing out something that is unknown. [B] learning information that is hidden. [C] making use of information that is hidden. [D] putting effort into something that is unknown.
【正确答案】
B
【答案解析】语义题。由题干定位至第二段，笫五句“But scientists are slowly teasing out exercise's impact on metabolism, appetite and body composition, though the consequences of exercise can vary”之后的for instance说明这是对前一句的举例说明，该句揭示了锻炼对男女新陈代谢的不同作用，这说明科学家们了解运动对新陈代谢的作用，由此可推知，teasing out exercise's impact是“了解运动作用”之意，由前一句巾的“Until recently, the bodily mechanisms involved were mysterious”可知，科学家们之前对此还不甚了解，[B]中的hidden与mysterious属于同一语义范畴，故[B]为答案。 [避错] 由“Until recently, the bodily mechanisms involved were mysterious”和But可以推出，teasing out不可能是testing out之意，因为了解未知事件的第一步是先有假设，再进行检验，既然本文没有提到具体的发现步骤，没有提到最初的似设，testing out也就毫无依据，排除[A]；同理，在还没有了解一件事之前，是不可能making use of的，排除[C]；而[D]中的putting effort只是说明努力了，但没有涉及结果，而文中直接给出运动对新陈代谢的作用这一结论，两者矛盾，排除[D]。
单选题
Which of the following statements may be CORRECT about exercise' [A] The more exercise you do, the more weight you will lose. [B] The dose of exercise recommended now might be reduced. [C] Moderate-intensity activities are the best exercise for dieters. [D] Dieters should take various forms of exercise to lose weight.
【正确答案】
B
【答案解析】推断题。按照题目顺序浏览第三段，末句指出：What the federal government currently recommends for weight loss is "a lot more than what many people would be able or willing to do, " Ravussin says，由此可以推断，如果想要达到前文提到的减肥效果，就应该减少联邦政府推荐的运动量，这样人们才能够坚持下来，愿意这样做，故[B]为答案。 [避错] 该段提到一组参与实验的人员的减重结果，“They all lost about the same amount of weight too about a pound a week.”，但并没有涉及是否加大运动量就可以减更多重量的问题。此外，这只是一个实验结果，不一定适用于所有人，故[A]无依据；倒数第二句指出“But in the exercising group, the dose of exercise required was nearly an hour a day of moderate-intensity activity.”，[C]是据此设计的绝对项，直接排除；文中只涉及锻炼的强度，没有提到锻炼的形式，[D]无依据，排除。
单选题
It can be inferred from the passage that ______ can give you an appetite. [A] increased blood concentrations of insulin [B] decreased blood concentrations of insulin [C] decreased blood concentrations of acylated ghrelin [D] increased blood concentrations of acylated ghrelin
【正确答案】
D
【答案解析】推断题。由题干中的acylated ghrelin和insulin定位至末段，倒数第五句中提到“But the women uniformly had increased blood concentrations of acylated ghrelin and decreased concentrations of insulin after the sessions in which they had eaten less than they had burned.”，由末句的结论“Exercise for many women increases the desire to eat.”可知，锻炼会使女性食欲增加。再结合该段第二句“when healthy young men ran for an hour and a half on a treadmill at a fairly high intensity, their blood concentrations of acylated ghrelin fell, and food held little appeal for the rest of that day. ”可知“increased blood concentrations of acylated ghrelin”会促进食欲，故[D]为答案。 [避错] 文中只在倒数第五句中提到decreased concentrations of insulin，但这是after the sessions in which they had eaten less than they had burned的结果，由第二句男士锻炼后的反应可以推断，这与锻炼后的食欲无关，排除[B]；显然，insulin“胰岛索”增加还是减少与食欲无关，排除[A]；[C]与文意矛盾，直接排除。
单选题
The best title for the passage is probably [A] Exercise and Weight Loss. [B] Weighing the Evidence on Exercise. [C] Effect of Exercise on Men and Women. [D] Calories, Exercise and Weight Loss.