39.Among“humanity's current problems” (Line 6, Para. 3), the chief concern of the scientists is _______.
A) the impoverishment of developing countries.
B) the explosion of the human population.
C) the reduction of biological diversity.
D) the effect of global warming.
注：第三段。C选项中reduction对应rob，diversity对应richness。
40.The author's purpose in writing this passage is ________.
A) to describe the difficulties in solving humanity's current problems.
B) to present the different views on humanity's current problems.
C) to analyze the contradiction between countries in dealing with humanity's current problems.
D) to point out that humanity's current problems can only be solved through the cooperation of nations.
注：看最后一句话，cooperation of nations 对应coordinated international efforts。
[Page80]
We sometimes think humans are uniquely vulnerable to anxiety, but stress seems to affect the immune defenses of lower animals too. In one experiment, for example, behavioral immunologist (免疫学家)Mark Laudenslger, at the University of Denver, gave mild electric shocks to 24 rats. Half the animals could switch off the current by turning a wheel in their enclosure, while the other half could mot. The rats in the two groups were paired so that each time one rat turned the wheel it protected both itself and its helpless partner from the shock. Laudenslager found that the immune response was depressed below normal in the helpless rats but not in those that could turn off the electricity. What he has demonstrated, he believes, is that lack of control over an event, not the experience itself, is what weakens the immune system.
注：1. vulnerable易受伤害的
2. immune defense 免疫系统
3. found之后是试验告诉我们的观点
4. depress压抑，de往下
Other researchers agree. Jay Weiss, a psychologist at Duke University School of Medicine, has shown that animals who are allowed to control unpleasant stimuli don't develop sleep disturbances or changes in brain chemistry typical of stressed rats. But if the animals are confronted with situations they have no control over, they later behave passively when faced with experiences they can control. Such findings reinforce psychologists' suspicions that the experience or perception of helplessness is one of the most harmful factors in depression.
注：1. 看第一句三个单词就知道本段内容和上一段相同。
2. passive被动的
21. Laudenslager's experiment showed that the immune system of those rats who could turn off the electricity ______.
A) was strengthened
B) was not affected
C) was altered
D) was weakened
注：定位文章第一段found之后
相关推荐：
英语六级考试阅读理解核心备考词汇归类汇总 2008年12月英语六级考试阅读理解模拟试题 备考大学英语四六级考试72种必备关键句型
