How would you like to sleep with one half your brain asleep and the other half awake? Dolphins sleep this way. Recently, scientists at Indiana State University have discovered that ducks sleep this way too. They found that ducks sleep half awake so they can rest and watch for danger at the same time.
After putting their ducks in a row and videotaping them, some researchers found ducks on the end of each row spent more time asleep with one eye open, apparently looking for predators.
“The more the ducks felt threatened, the more they slept with one eye open,” said lead author Niels C. Rattenborg, a graduate student at Indiana State University, Terre Haute. “The unique aspect is not that they do it, but that they control it. When they sleep at the edge of a group, they tend to realize greater danger, so they spend more time sleeping with one half of their brain.” Ducks with one eye open were still awake enough to detect predators, said the authors of the study, which appears today in the journal Nature.
The researchers studied four groups of four ducks held in plastic boxes, which were arranged in a row. Ducks on the end were found to sleep with one eye open 31.8 per cent of the time, pared to 12.4 percent of the time for ducks in the central position.
Also, ducks in the central position did not open one eye more than the others, while ducks on each end kept the eye facing away from the group open 86.2 per cent of the time. Brain wave readings of the ducks showed that the half of the brain receiving signals from the closed eye indicated that half of the brain was sleeping. Signals from the half of the brain receiving signals from the open eye showed a state between fully awake and asleep.
【小题1】The under lined word “predator” is most likely to mean .A．an animal that is likely to be friends with ducksB．a human being who looks after and feeds ducksC．a scientist who does research work on animalsD．an animal that hunts, kills and eats other animals【小题2】Ducks at the end of each row sleep with one eye open because .A．they are looking for foodB．they are watching out for dangerC．they want to enjoy the sceneryD．they are unique in their sleeping habit【小题3】Which of the following is true according to the passage?A．Ducks with one eye open at the edge can still enjoy a certain degree of sleep.B．Ducks with less sense of duty usually choose to stay in the center of a row.C．Ducks on the northern end of a row would keep their eye facing the south open.D．A video tape recorder was the only electronic device used in the experiment.D
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(答案→)D
解析：文章介绍了海豚和鸭子在休息的时候有一半大脑是清醒的，一半是休息的，在休息时有一只眼睛也是不断睁开的，研究者们也做了一系列的实验来证明他们是这么做的，并且了解了这么做的原因，主要是为了防止可能会出现的危险。
【小题1】 D细节理解题。They found that ducks sleep half awake so they can rest and watch for danger at the same time. 研究员们发现，鸭子在休息时一半是清醒的，因此他们能够同时注意危险；The more the ducks felt threatened, the more they slept with one eye open鸭子越感觉危险，他们睡觉时一只眼睛睁得越多。由此可知他们睡觉睁一只眼睛是为了寻找可能出现的危险。故答案应为D。
【小题2】B细节理解题。some researchers found ducks on the end of each row spent more time asleep with one eye open, apparently looking for predators.句意为：一些研究员发现，在每队边上的鸭子花费更多的时间睁着眼睛睡觉，很明显他是是警惕危险；When they sleep at the edge of a group, they tend to realize greater danger, so they spend more time sleeping with one half of their brain.当他们在边的时候，他们往往会意识到更大的危险，因此他们花费更多的时间保持他们大脑的清醒。故答案应为B。
【小题3】A细节判断题。文章第一自然段说明鸭子和海豚睡觉时大脑一半是清醒的一半是休息的，因此在边上的鸭子也有一定程度的休息是正解的。Ducks with less sense of duty usually choose to stay in the center of a row.没有责任感的鸭子通常选择在一排的中间，文章里没有说明鸭子是选地方休息的；Ducks on the northern end of a row would keep their eye facing the south open文中没有提到哪个方向的鸭子面朝向哪个方向；A video tape recorder was the only electronic device used in the experiment.文中提到了这个设备，但没说明是唯一的，故答案A是正确的。
【考点】考查科普环保类文章的阅读理解。