问大家两道逻辑，谢谢了！！！

lllmmm · 发表于 2011-6-16 23:50:38

第一道：d3. (24275-!-item-!-188;#058&000768)

The prairie vole, a small North American grassland rodent, breeds year-round, and a group of voles living together consists primarily of an extended family, often including two or more litters. Voles commonly live in large groups from late autumn through winter; from spring through early autumn, however, most voles live in far smaller groups. The seasonal variation in group size can probably be explained by a seasonal variation in mortality among young voles.

Which of the following, if true, provides the strongest support for the explanation offered?

(A) It is in the spring and early summer that prairie vole communities generally contain the highest proportion of young voles.
(B) Prairie vole populations vary dramatically in size from year to year.
(C) The prairie vole subsists primarily on broad-leaved plants that are abundant only in spring.
(D) Winters in the prairie voles' habitat are often harsh, with temperatures that drop well below freezing.
(E) Snakes, a major predator of young prairie voles, are active only from spring through early autumn.

第二道：24. (29155-!-item-!-188;#058&003857) C

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.

tsx190 · 发表于 2011-8-7 21:09:57

The prairie vole, a small North American grasslandrodent, breeds year-round, and a group of voles living together consistsprimarily of an extended family, often including two or more litters(一窝). Voles commonly live in large groups from lateautumn through winter; from spring through early autumn, however, most voleslive in far smaller groups. The seasonalvariation in group size can probably be explained by a seasonal variation inmortality among young voles.

Which of the following, if true, provides thestrongest support for the explanation offered?
背景： V是群居生物
前提1： V在秋天到冬天是群居，从春天到早秋是单独（以更小的group活动）
结论：这种size随季节的改变，是由于小V的死亡率导致的

要support，在小V的死亡率和size季节改变之间建立逻辑关系
(A) It is in the spring and early summer thatprairie vole communities generally contain the highest proportion of youngvoles.
(B) Prairie vole populations vary dramatically insize from year to year.
(C) The prairie vole subsists primarily on broad-leavedplants that are abundant only in spring.
(D) Winters in the prairie voles' habitat areoften harsh, with temperatures that drop well below freezing.
(E) Snakes, a major predator of young prairievoles, are active only from spring through early autumn.（由于snake在这段时间活动频繁，可知小V死亡率高）

问大家两道逻辑，谢谢了！！！

所属分类: GMAT考试

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