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标题: 求教prep cr1 第24题 B和C的判别！不胜感谢！ [打印本页]

作者: masushuang 时间: 2012-4-8 11:45
标题: 求教prep cr1 第24题 B和C的判别！不胜感谢！
答案是C，想知道B为什么错？？？
好心人解释解释~

作者: masushuang 时间: 2012-4-8 11:46
是prep2007~

作者: masushuang 时间: 2012-4-8 11:49
24. (29155-!-item-!-188;#058&003857)

Tiger beetles are such fast runners that they can capture virtually any nonflying insect. However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack.

erhaps they cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.

Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?

(A) When a prey insect is moved directly toward a beetle that has been chasing it, the beetle immediately turns and runs away without its usual intermittent stopping.
(B) In pursuing a moving insect, the beetles usually respond immediately to changes in the insect's direction, and pause equally frequently whether the chase is up or down an incline.
(C) The beetles maintain a fixed time interval between pauses, although when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause.
(D) If, when a beetle pauses, it has not gained on the insect it is pursuing, the beetle generally ends its pursuit.
(E) When an obstacle is suddenly introduced just in front of running beetles, the beetles sometimes stop immediately, but they never respond by running around the barrier.

作者: aina1314 时间: 2012-4-8 18:51
非牛牛
我试一下，文中说tiger beetle停一下的原因，要么是视觉不好，要么是需要休息。问支持其中一个假设，削弱另外一个，B选项说它经常能转变方向去追昆虫，然后休息。这就说明它视觉好，削弱了视觉，随后就要加强休息那个结论，但是B选项后半段说无论抓不抓了都需要休息一下。证明追虫子的时候不是因为体力的原因，同样是削弱了需要休息这个结论。2个都是削弱，而文章问的是一个加强，一个削弱。所以不对。 C选项说及时那虫子在那要飞走了，它也要休息下，加强了需要休息。自然也就否定了另外一个。

作者: masushuang 时间: 2012-4-8 23:34
谢谢~我想我有点捉摸出来了。C的前半段明显是加强体力原因的，后半段说，本来静止的虫子要飞了，他就会加快速度追上去，说明视力没有问题。

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