Our bodies are wonderfully skilful at maintaining balance. When the temperature jumps, we sweat to cool down. When our blood pre

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问题     Our bodies are wonderfully skilful at maintaining balance. When the temperature jumps, we sweat to cool down. When our blood pressure falls, our hearts pound to compensate. As it turned out, though, our natural state is not a steady one. Researchers are finding that everything from blood pressure to brain function varies rhythmically with the cycles of sun, moon and seasons. And their insights are yielding new strategies for keeping away such common killers as heart disease and cancer. Only one doctor in 20 has a good knowledge of the growing field of "chronotherapeutics", the strategic use of time (chronos) in medicine. But according to a new American Medical Association poll, three out of four are eager to change that "The field is exploding", says Michael Smolensky. "Doctors used to look at us like, ’What space ship did you guys get off ?’ Now they’re thirsty to know more. "
    In medical school, most doctors learn that people with chronic conditions should take their medicine at steady rates. "It’s a terrible way to treat disease," says Dr. Richard Martin. For example, asthmatics (气喘患者) are most likely to suffer during the night. Yet most patients strive to keep a constant level of medicine in their blood day and night, whether by breathing in on an inhaler (吸入器) four times a day or taking a pill each morning and evening. In recent studies, researchers have found that a large midafternoon dose of a bronchodilator (支气管扩张 剂) can be as safe as several small doses, and better for preventing nighttime attacks.
    If the night belongs to asthma, the dawn belongs to high blood pressure and heart disease. Heart attacks are twice as common at 9 a. m. as at 11 p. m. Part of the reason is that our blood pressure falls predictably at night, then peaks as we start to work for the day. "Doctors know that," says Dr. Henry Black of Chicago Medical Center, "but until now, we haven’t been able to do anything about it. " Most blood pressure drugs provide 18 to 20 hours of relief. But because they’re taken in the morning, they’re least effective when most needed. "You take your pill at 7and it’s working by 9," says Dr. William White of the University of Connecticut Health Center. "But by that time you’ve gone through the worst four hours of the day with no protection,"Bedtime dosing would prevent that lapse, but it would also push blood pressure to dangerously low levels during the night.
According to the passage, how do human bodies maintain balance?

选项 A、They adjust themselves timely in line with their physical conditions.
B、People increase or lower the body temperature by sweating.
C、People’s hearts pound to compensate when the blood pressure goes up.
D、Both B and C

答案A

解析 本题是一道具体细节题。问本文指出人体怎样保持平衡。利用查阅式阅读法,我们可在第一段前三句中找到相关信息。这部分指出,我们的身体很善于保持平衡。例如,体温上升时,我们通过出汗降温;血压下降时,我们心跳速度加快,补充压力。这都是指身体的自我调节能力,以保持其自身的平衡。因此,本题的正确答案应是A“它们根据身体状况作及时调整”。
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