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标题: prep逻辑求教 [打印本页]

作者: ericwilliam 时间: 2011-10-30 11:29
标题: prep逻辑求教

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。可是不太理解B是什么意思，求高人指教。thx

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