单选题 At his research clinic in Dallas, psychologist Jasper Smits is working on an unorthodox treatment for anxiety and mood disorders, including depression. It is not yet widely accepted, but his treatment is free and has no side effects. Compare that with antidepressant drugs, which cost Americans $10 billion each year and have many common side effects: sleep disturbances, nausea, tremors, changes in body weight. This intriguing new treatment? It's nothing more than exercise.
In 1999, Duke University researchers demonstrated in a randomized controlled trial that depressed adults who participated in an aerobic-exercise plan improved as much as those treated with medication. Subsequent trials have repeated these results, showing again and again that patients who follow aerobic-exercise plans see improvement in their depression comparable to that of those treated with medication, and that both groups do better than patients given only a placebo. But exercise trials on the whole have been small, and most have run for only a few weeks; some are plagued by methodological problems. Still, despite limited data, the trials all seem to point in the same direction: exercise boosts mood. It not only relieves depressive symptoms but also prevents them from recurring.
Molecular biologists and neurologists have begun to show that exercise may alter brain chemistry in much the same way that antidepressant drugs do—regulating the key neurotransmitters serotonin and norepinephrine. At the University of Georgia, neuroscience professor Philip Holmes and his colleagues have shown that over the course of several weeks, exercise can switch on certain genes that increase the brain's level of galanin, a peptide neurotransmitter that appears to tone down the body's stress response by regulating another brain chemical, norepinephrine.
The result is that exercise primes the brain to show less stress in response to new stimuli. In the case of lab rats and mice, those stimuli include being plunged into very cold water or being suspended by the tail. And while those are not exactly problems most people face, the thinking is that the human neurochemical response may well react similarly, with exercise leaving our brain less susceptible to stress in the face of harmless but unexpected events, like missing an appointment or getting a parking ticket. A little bit of mental strain and excess stimulation from exercise, in other words, may help us to keep day-to-day problems in perspective.
Researchers wonder whether this interaction between body and brain may, evolutionarily speaking, be unchangeable. "It occurs to us that exercise is the more normal or natural condition and that being sedentary is really the abnormal situation, "Holmes says.

单选题 According to the first paragraph, antidepressant drugs______.

【正确答案】 C

【答案解析】[试题类型] 具体信息题。
[解题思路] 根据题干要求定位至第一段。该段指出，抗抑郁药物耗费美国人大量的金钱(cost Americans $10 billion each year)，同时伴有许多常见的副作用(have many common side effects)。由此可知，在美国的治疗中，抗抑郁药物的使用是很广泛的，故选项[C]正确。
[干扰排除] 由第一段可知，非传统治疗手段(unorthodox treatment)即运动疗法，是免费且无副作用的(free and has no side effects)，但文中第一段没有将两者的治疗效果作比较(虽然第二段有比较，但题干限定为第一段)，故排除选项[A]和[D]。由文中which cost Americans $10 billion each year可知，抗抑郁药物不是新的不常见的治疗方法，故排除选项[B]。

单选题 What can be learned from the Duke University experiment?

【正确答案】 B

【答案解析】[试题类型] 具体信息题。
[解题思路] 根据关键词researchers at Duke University定位至第二段。该段段末指出，一系列的研究都表明，运动让人心情舒畅(exercise boosts mood)，缓解抑郁症状(relieves depressive symptoms)，并且阻止其再次发生(prevents them from recurring)。由此可知，运动有助于治愈抑郁，故正确选项为[B]。
[干扰排除] 第二段指出，在参与运动试验的人中，有多数人只坚持运动了几个星期，并且有一部分人因方法方面的问题而饱受痛苦(plagued by methodological problems)，由此可知，运动疗法不是容易掌握的，所以选项[A]“运动疗法容易掌握且很划算”是错误的。文中只是提到了运动疗法在治疗抑郁症状方面疗效显著，但没有提及该疗法是否会代替药物治疗或者受到医生的广泛推崇，故排除选项[C]、[D]。

单选题 Philip Holmes discovered that exercise could______.

【正确答案】 B

【答案解析】[试题类型] 具体信息题。
[解题思路] 根据题干关键词Philip Homes定位至第三段。该段指出，霍姆斯及其同事经过几个星期的研究发现，运动能激活某种增加脑部甘丙肽的基因，而甘丙肽可以通过调节肾上腺素减少压力对身体的影响(exercise can switch on certain genes...tone down the body's stress response by regulating another brain chemical, norepinephrine)，故选项[B]“运动促使某种基因发挥有利作用”符合文意。
[干扰排除] 第三段第一句提到分子生物学家和神经学家认为运动可以改变脑部化学物质(alter brain chemistry)，第二句列出Holmes的研究发现进一步证实了这个观点。这说明“运动能改变脑部化学物质”并不是Holmes发现的，故排除选项[A]。同样，第二段提到，运动疗法以及药物治疗都比只用安慰剂的效果要好，并且该段段末提到，运动可以缓解抑郁症状(relieve depressive symptoms)。选项[C]、[D]信息正确，但都不是：Holmes的研究成果，故排除。

单选题 It can be inferred from the passage that______.

【正确答案】 D

【答案解析】[试题类型] 推理引申题。
[解题思路] 由第四段第一句exercise primes the brain to show less stress in response to new stimuli可知，锻炼可以使大脑为外界的新刺激做好充足的准备，接下来后文通过实验指出其具体原因，A little bit of mental strain...may help us to keep day-to-day problems，即运动中的精神紧张及刺激有助于我们正确看待日常问题。由此可知，是运动中的精神紧张使我们为外界的刺激做好准备，从而表现出较小的压力，故正确选项为[D]。
[干扰排除] 文中提到运动疗法以及药物治疗都可以帮助大脑缓解压力，由此可以推知大脑无法自动处理压力，故排除选项[A]。第四段末句指出，运动带来的紧张和刺激有助于我们正确看待日常问题，而非忘记(forget about)日常问题，故排除选项[B]。由第四段第三句可知，运动可以使我们在面对有惊无险的事情时，不容易受到太大的影响(leaving our brain susceptible to stress in the face of harmless but unexpected events)，但文中并没有说这类事情不会给我们带来大的影响，故排除选项[C]。

单选题 The last paragraph suggests that______.

【正确答案】 B

【答案解析】[试题类型] 推理引申题。
[解题思路] 由文章最后一段第一句Researchers wonder whether this interaction between body and brain may...be unchangeable呵知，科学家不确定，大脑与身体之间的互相作用是否是不可改变的，言下之意，这种相互作用是有改变的可能的，故正确选项为[B]。
[干扰排除] 同样由文中最后一段第一句可知，科学家确定大脑与身体之间是互相作用的，不确定的是两者之间的相互作用是否不可改变，故排除选项[A]。由最后一段第二句exercise is the more normal...being sedentary is really the abnormal situation可知，运动是自然的状态而久坐属于异常情况，故排除选项[C]，同样由该句可知，运动是比久坐更常见更自然的状态，故选项[D]的表述与原文相反。