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这两题选项不一样，两个题的正确选项不一样 重贴Prep的题 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. Perhaps 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. 答案是C，我选了B。我知道B错，是因为它只讲了跟视力有关，支持了一项，却没有谈到体力，所以没有削弱另一个原因，可是C为什么对？我觉得C也是只说速度更快，证明跟体力有关，但是也没削弱关于视力原因啊？急问！！！ | 
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发表于 2006-2-3 15:32:00
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