题目内容
“Humans should not try to avoid stress any more than they would shun food, love or exercise.” said Dr. Hans Selye, the first physician to document the effects of stress on the body. While here’s no question that continuous stress is harmful, several studies suggest that challenging situations in which you’re able to rise to the occasion can be good for you.
In a 2001 study of 158 hospital nurses, those who faced considerable work demands but coped with（设法处理） the challenge were more likely to say they were in good health than those who felt they couldn’t get the job done.
Stress that you can manage may also boost immune(免疫的) function. In a study at the Academic Center for Dentistry in Amsterdam, researchers put volunteers through two stressful experiences. In the first, a timed task that required memorizing a list followed by a short test, subjects believed they had control over the outcome. In the second, they weren’t in control: They had to sit through a gory(血淋淋的) video on surgical procedures. Those who did go on the memory test had an increase in levels of immunoglobulin A, an antibody that's the body’s first line of defense against germs. The video-watchers experienced a downturn in the antibody.
Stress prompts the body to produce certain stress hormones（荷尔蒙）. In short bursts these hormones have a positive effect, including improved memory function. “They can help nerve cells handle information and put it into storage,” says Dr. Bruce McEwen of Rockefeller University in New York. But in the long run these hormones can have a harmful effect on the body and brain.
“Sustained stress is not good for you,” says Richard Morimoto, a researcher at Northwestern University in Illinois studying the effects of stress on longevity(长寿), “It’s the occasional burst of stress or brief exposure to stress that could be protective.”
1.The passage is mainly about ________.
A. the benefits of manageable stress
B. how to avoid stressful situations
C. how to cope with stress effectively
D. the effects of stress hormones on memory
2. The underlined word “shun” (Line 1, Para.1) most probably means________.
A. cut down on
B. stay away from
C. run out of
D. put up with
3. We can conclude from the study of the 158 nurses in 2001 that ________.
A. people under stress tend to have a poor memory
B. people who can’t get their job done experience more stress
C. doing challenging work may be good for one’s health
D. stress will weaken the body’s defense against germs
4.Dr. Bruce McEwen of Rockefeller University believes that ________.
A. a person’s memory is determined by the level of hormones in his body
B. stress hormones have lasting positive effects on the brain
C. short bursts of stress hormones enhance memory function
D. a person’s memory improves with continued experience of stress
1.A2.B3.C4.C
【解析】
名师伴你成长课时同步学练测系列答案Below is a selection from a popular science book.
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If blood is red, why are veins (静脉) blue? Actually, veins are not blue at all. They are more of a clear, yellowish color. Although blood looks red when it’s outside the body, when it’s sitting in a vein near the surface of the skin, it’s more of a dark reddish purple color. At the right depth, these blood-filled veins reflect less red light than the surrounding skin, making them look blue by comparison. Which works harder, your heart or your brain? That kind of depends on whether you’re busy thinking or busy exercising. Your heart works up to three times harder during exercise, and shifts enough blood over a lifetime to fill a supertanker（超级油轮）. But, in the long run, your brain probably tips it, because even when you’re sitting still your brain is using twice as much energy as your heart, and it takes four to five times as much blood to feed it. Why do teeth fall out, and why don’t they grow back in grown-ups? Baby (or “milk”) teeth do not last long; they fall out to make bigger room for bigger, stronger adult teeth later on. Adult teeth fall out when they become damaged, decayed（腐烂）and infected by bacteria. Once this second set of teeth has grown in, you’re done. When they’re gone, they are gone. This is because nature figures you’re set for life, and what controls regrowth of your teeth switches off. Do old people shrink（收缩）as they age? Yes and no. Many people do get shorter as they age. But, when they do, it isn’t because they’re shrinking all over. They simply lose height as their spine (脊柱) becomes shorter and more curved due to disuse and the effect of gravity (重力). Many (but not all) men and women do lose height as they get older. Men lose an average of 3-4 cm in height as they age, while women may lose 5 cm or more. If you live to be 200 years old, would you keep shrinking till you were, like 60 cm tall, like a little boy again? No, because old people don’t really shrink! It is not that they are growing backwards—their legs, arms and backbones getting shorter. When they do get shorter, it’s because the spine has shortened a little. Or, more often, become more bent and curved. Why does spinning make you dizzy)? Because your brain gets confused between what you’re seeing and what you’re feeling. The brain senses that you’re spinning using special gravity-and-motion-sensing organs in your inner ear, which work together with your eyes to keep your vision balance stable. But when you suddenly stop spinning the system goes out of control, and your brain thinks you’re moving while you’re not. Where do feelings and emotions come from? Mostly from an ancient part of the brain called the limbic system（边缘系统）. All mammals have this brain area — from mice to dogs, cats, and humans. So all mammals feel basic emotions like fear, pain and pleasure. But since human feelings also involve other, newer bits of the brain, we feel more complex emotions than any other animal on this planet. If exercise wears you out, how can it be good for you? Because our bodies adapt to everything we do to them. And as far as your body is concerned, it’s “use it, or lose it”! It’s not that exercise makes you healthy, it’s more that a lack of exercise leaves your body weak and easily affected by disease. |
1.What is the color of blood in a vein near the surface of the skin?
A. Blue B. Light yellow
C. Red D. Dark reddish purple
2.Why do some old people look a little shrunken as they age?
A. Because their spine is in active use.
B. Because they are more easily affected by gravity.
C. Because they keep growing backwards.
D. Because their spine becomes more bent.
3.Which of the following statements about our brain is true?
A. In the long run, our brain probably works harder than our heart.
B. When our brain senses the spinning, we will feel dizzy.
C. The brains of the other mammals are as complex as those of humans.
D. Our feelings and emotions come from the most developed area in our brain.
4.What is the main purpose of the selection?
A. To give advice on how to stay healthy.
B. To provide information about our body.
C. To challenge new findings in medical research.
D. To report the latest discoveries in medical science.