单选题 Exercise is one of the few factors with a positive role in long-term maintenance of body weight. Unfortunately, that message has not gotten through to the average American, who would rather try switching to "light" beer and low-calorie bread than increase physical exertion. The Centers for Disease Control, for example, found that fewer than one-fourth of overweight adults who were trying to shed pounds said they were combining exercise with their diet. In rejecting exercise, some people may be discouraged too much by caloric-expenditure charts: for example, one would have to briskly walk three miles just to work off the 275 calories in one delicious Danish pastry(小甜饼). Even exercise professionals concede half a point here. "Exercise by itself is a very tough way to lose weight," says York Onnen, program director of the President's Council on Physical Fitness and Sports. Still, exercise's supporting role in weight reduction is vital. A study at the Boston University Medical Center of overweight police officers and other public employees confirmed that those who dieted without exercise regained almost all their old weight, while those who worked exercise into their daily routine maintained their new weight. If you have been sedentary(极少活动的)and decide to start walking one mile a day, the added exercise could burn an extra 100 calories daily. In a year's time, assuming no increase in food intake, you could lose ten pounds. By increasing the distance of your walks gradually and making other dietary adjustments, you may lose even more weight.

单选题 What is said about the average American in the passage?

【正确答案】 B

【答案解析】解析：在第一段中提到“that message has not gotten through to the average American，who wouldrather try switching to“light”beer and low—calorie bread than increase physical exertion”。这里的that message(那信息)肯定应该在前一句，也就是“Exercise is one of the few factors with a positive role in long—term maintenance ofbody weight”(锻炼是对长期保持体重起积极作用的少有因素之一)。词组“has not gotten through to”指的是“在……中并不流行”．这里的意思就是那一信息对于一般美国人来说并没有受到重视。who引导了一个从句，是对一般美国人的描述。这里使用了would rather…than(宁可，也不)句型，意思是美国人宁可把兴趣投向淡爽啤酒和低卡路里面包，也不增加身体锻炼。四个选项中，B符合文意。

单选题 Some people dislike exercise because( ).

【正确答案】 B

【答案解析】解析：第二段专门对有些人不喜欢锻炼的原因进行了说明，主要有两句话。第一句“some peoplemay be discouraged too much by caloric-expenditure charts”，这句话的意思是“卡路里消耗表会使有些人非常泄气”，后面给出了原因，即锻炼消耗的卡路里太少。由此看来，并不是他们觉得参考卡路里消耗表麻烦，D的说法不对。第二句借专业人士之口说出了原因“Exercise by itself is a very tough way to lose weight．”“tough”这个倒强调艰苦、艰难性，也就是说用锻炼来减肥太过于艰难了。与前面消耗卡路里的说法结合起来就是：因为锻炼消耗的卡路里非常少，所以要想减肥的话，锻炼的投入要非常大才能产生效果。

单选题 "Even exercise professionals concede half a point here"(Line 3,Para 2)means "They( )".

A、 agree that the calories in a small piece of pastry can be difficult to work off by exercise
B、 partially believe diet plays a supporting role in weight reduction
C、 are not fully convinced that dieting can help maintain one's new weight
D、 are not sufficiently informed of the positive role of exercise in losing weight

【正确答案】 A

【答案解析】解析：“一块小甜饼中的卡路里通过锻炼消耗掉是困难的”这句话是用来支持“锻炼身体实际上对于减肥来说费力不讨好”这个观点的，所以他们可以说是承认“一块小甜饼中的卡路里通过锻炼消耗掉是困难的”这句话有一定的道理。A的说法正确。

单选题 What was confirmed by the Boston University Medical Center's study?

【正确答案】 C

【答案解析】解析：第三段对波士顿大学医疗中心的研究做了描述，其中直接出现了“confirm”一词，验证的内容是“those who dieted without exercise regained almost all—their old weight，while those who worked exercise intotheir daily routine maintained their new weight”，那些节食而不锻炼的人几乎全部反弹到原来的体重，而那些把锻炼身体列入日常项目的人则保持了减肥后的体重。C的说法正确。

单选题 What is the author's purpose in writing this article?

【正确答案】 D

【答案解析】解析：从前面的分析可知，这篇文章主要讲的是锻炼在减肥中的重要性，A和C提到的人物和机构都只是作者用来支撑这一观点的论据，可以首先排除。B的说法也是明显错误的．文章讲的是如何保持合适的体重，而不是在强调其重要性。作者强调了身体锻炼在减肥中的重要性，向人们说明最好在节食的同时参加体育锻炼，这可以说是介绍了一种最好的减肥方法。