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题库 / Prep2012-CR-70
Frobisher, a sixteenth-century English explorer, had soil samples from Canada's Kodlunarn Island examined for gold content. Because high gold content was reported, Elizabeth I funded two mining expeditions. Neither expedition found any gold there. Modern analysis of the island's soil indicates a very low gold content.Thus the methods used to determine the gold content of Frobisher's samples must have been inaccurate.
Which of the following is an assumption on which the argument depends?
The gold content of the soil on Kodlunarn Island is much lower today than it was in the sixteenth century.
The two mining expeditions funded by I did not mine the same part of Kodlunarn Island.
The methods used to assess gold content of the soil samples provided by Frobisher were different from those generally used in the sixteenth century.
Frobisher did not have soil samples from any other Canadian island examined for gold content.
Gold was not added to the samples collected by Frobisher before the samples were examined.
P1：以前，F报告说有 high gold content 但实际却没找到gold:
P2：现代技术检测 low gold content
C: F的检测方法不准
Assuption假设：
Gold was not added to the samples collected by Frobisher before the samples were examined. 在样本检测前金子没有被加入样本；
取反：. 在样本检测前金子被被加入样本→所以才能测出金含量高→所以F的测量方法没问题，削弱了原结论
E取非 如果金子是故意加到土壤里的 说明之前得出岛上有金子的结论和method都没错 取非削弱method有误这个结论 反之加强
探险家F在16世纪带回来的土壤检测出了高含量金子。在之后的两次取样中没有一次发现有金子，并且现代检测技术发现岛上土壤其实含金量很低。
结论是用于检测F的土壤含金技术肯定是错误的。问assume
choice a, 岛上今天的土壤含金量比16世纪低很多。取非，今天的土壤含金量等于甚至高于16世纪的土壤含金量。无法削弱结论
choice e, 金子不是刻意由F加入土壤样本中的。correct
E取反就可以理解了。。。加了金子含量高，不能说明测量方法不准确，weaken 了conclusion
E也很牵强，为什么有人会这样做。。。
还有，假设题对含有否定词的选项要敏感，看到直接取反往往能直接获得正确答案
错选D，其实D是与文中的背景相矛盾的，肯定不行。
F是个16世纪英国探险家，从加拿大K岛拿回土壤样本检测金含量。因为测出金含量高，伊丽莎白一世资助了两个开矿队。两个开矿队都没有找到金子。K岛的土壤分析表明金含量低。因此用来测F样本金含量的方法不精确。 求假设即加强，等同取非求削弱--方法准，找一个选项让方法不准了。
A. K岛的金含量现在比16世纪低；测试方法就是16世纪的，跟现在含金量多少无关
B. 两个开矿队没有开采K岛的同一区域；无关，排
C. 用来测F样本的方法和16世纪其他方法不同；无关比较，排
D. F没有从其他岛上取样本来测金含量；其他岛，跳出范围，排
E. 在样本检测前金子没有被加入样本；取反即有金子加入样本，测出金含量高不能说明测量方法不精确，取反削弱结论，正确
果因，给果另一个因