托福听力荟萃 47（在线收听）

Did you ever wonder why it is that most people are "______" to sleep at night instead of during the day? If there's something about the cycle of light and dark that's telling us when to sleep, then shouldn't the sleep cycle of a blind person be different? As it turns out, many blind people—people with no visual perception of light at all—do have the same sleep cycle as______people. So now you're wondering, "How can this happen?" The answer is:______, one hormone in particular. It's called______. In sighted people, the level of melatonin goes up at night, or when it's dark, and goes down in the day, or when it's light. It's believed that it's the presence of this hormone in the blood that gives us the______to sleep. If an increase in melatonin level "programs" sighted people to sleep at night, then what about blind people? A researcher, named Dr. Charles Czeisler, tells about an interesting experiment. He tried shining a bright light into the eyes of some blind people. When he did this, he noticed that the level of the melatonin in the blood of these subjects went down just as it would do for sighted people. Somehow, the eyes of these subjects, even though they were damaged and had no visual perception of light, could tell their brain when there was more or less light. Now, this doesn't work for all blind people; in fact, most of Czeisler's subjects had no______response to light at all. Further research may be able to explain this sensitivity to light______the type of blindness of the subject.

【填空答案】

programme: v. 编程，计划，安排

sighted: adj. 看得见的，有视力的

hormone: n. ［C］荷尔蒙，激素

melatonin: n. ［C］退黑激素

urge: n. ［C］强烈欲望

hormonal: adj. 荷尔蒙的，激素的

intermsof: 在……方面

【听力原文】

Did you ever wonder why it is that most people are "programmed" to sleep at night instead of during the day? If there's something about the cycle of light and dark that's telling us when to sleep, then shouldn't the sleep cycle of a blind person be different? As it turns out, many blind people --- people with no visual perception of light at all --- do have the same sleep cycle as sighted people.

So now you're wondering, "How can this happen?" The answer is: hormones --- one hormone in particular. It's called melatonin. In sighted people, the level of melatonin goes up at night (or when it's dark) and goes down in the day (or when it's light). It's believed that it's the presence of this hormone in the blood that gives us the urge to sleep. If an increase in melatonin level "programs" sighted people to sleep at night, then what about blind people?

A researcher named Dr. Charles Czeisler, tells about an interesting experiment. He tried shining a bright light into the eyes of some blind people. When he did this, he noticed that the level of the melatonin in the blood of these subjects went down --- just as it would do for sighted people. Somehow, the eyes of these subjects, even though they were damaged and had no visual perception of light, could tell their brain when there was more or less light. Now, this doesn't work for all blind people; in fact, most of Czeisler's subjects had no hormonal response to light at all. Further research may be able to explain this sensitivity to light in terms of the type of blindness of the subject.

【参考译文】

难道你不知道为什么它是大多数人的“程序”，晚上睡觉白天，而不是？如果有关于光明与黑暗周期的东西，这就是告诉我们什么时候睡觉，那么应该不是盲目的人的睡眠周期是不同的吗？事实证明，许多盲人---没有---在所有的视觉感知的人，有远见的人有相同的睡眠周期。所以，现在你想知道，“这是怎样发生的？”答案是：激素---一种特别的激素。它被称为褪黑激素。有远见的人，褪黑激素的水平会在夜间（或当它是黑暗），并在当天（或当它的光）。它相信，它的存在，这种激素在血液中，让我们睡的冲动。如果增加褪黑激素水平的“方案”看见人在晚上睡觉，那么盲人呢？名叫查尔斯Czeisler博士，研究员，讲述了一个有趣的实验。他试图到一些盲人的眼睛闪耀着耀眼的光芒。当他这样做时，他注意到，这些受试者血液中的褪黑激素的水平了---只是因为它会做的有识之士。不知何故，这些科目的眼睛，即使他们被损坏，没有光线的视觉感知，可以告诉他们的大脑有更多或更少的光。现在，这并不工作，所有失明人士，事实上，Czeisler的大部分科目有没有点亮所有的荷尔蒙反应。进一步的研究也许能够解释的主体失明对光线敏感。