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题库 / Prep2012-CR-43
Two centuries ago, Tufe Peninsula became separated from the mainland, isolating on the newly formed Tufe Island a population of sunflowers.
This population's descendants grow to be, on average, 40 centimeters shorter than sunflowers found on the mainland. Tufe Island is significantly drier than Tufe Peninsula was. So the current average height of sunflowers is undoubtedly at least partially attributable to changes in Tufe's environmental conditions.
Which of the following is an assumption on which the argument depends?
There are no types of vegetation on Tufe Island that are known to benefit from dry conditions.
There were about as many sunflowers on Tufe Peninsula two centuries ago as there are on Tufe Island today.
The mainland's environment has not changed in ways that have resulted in sunflowers on the mainland growing to be 40 centimeters taller than they did two centuries ago.
The soil on Tufe Island, unlike that on the mainland, lacks important nutrients that help sunflowers survive and grow tall in a dry environment.
The 40-centimeter height difference between the sunflowers on Tufe Island and those on the mainland is the only difference between the two populations.
题型：果因推理（现象解释题）
评估：CQ1找他因，解释现象。CQ2：因果联系link
原文：
（过去）两个世纪前，T Peninsula（半岛） 分离= mainland（旧大陆） +T island（新小岛），T island有新的向日葵。
（现在）
T island的向日葵后代 比mainland的向日葵短 40 cm。①现象（果）--后发生
T Island 比T Peninsula（=mainland旧大陆）气候干燥。② 解释（因）--先发生
所以，出现①现象的原因是②
问assumption:【取非的选项 can 削弱 原文的结论】
选项B（√）
mainland's environment 旧大陆环境并没有改变 → mainland旧大陆的向日葵 比两个世纪前高出40cm。
--取非：mainland 旧大陆环境改变 → mainland的向日葵 比两个世纪前高出40cm。（【他因削弱】了原结论，说明T island 的花变矮不是因为②（本岛气候干），而是其他原因（mainland's environment 旧大陆环境的变化）
选项C（×）
The soil on Tufe Island, unlike that on the mainland, lacks important nutrients that help sunflowers survive and grow tall in a dry environment.
与mainland旧大陆不同，T Island的土壤缺乏养分，这种养分有助于向日葵在干燥环境中生长。
--取非：T island 的土壤 含有养分，这种养分有助于向日葵在干燥环境中生长。（则是T island向日葵就不会那么矮，弥补了气候干的影响，所以加强原结论：出现①现象的原因是②，说明就是T island的气候干燥导致是T island的向日葵长得矮。）
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