※ 引述《best1yiyi (yoyo)》之铭言： : TN-19 #29 : Lofgren’s disease has been observed frequently in commercially raised cattle : but very rarely in chickens.Both cattle and chickens raised for meat are : often fed the type of feed that transmits the virus that causes the : disease.Animals infected with the virus take more than a year to develop : symptoms of Lofgren’s disease, however, and chickens commercially raised for : meat, unlike cattle, are generally brought to market during their first year : of life. : Which of the following is most strongly supported by the information : provided? : A.The virus that causes Lofgren’s disease cannot be transmitted to human : beings by chickens. : B.There is no way to determine whether a chicken is infected with the Lofgren : s disease virus before the chicken shows symptoms of the disease. : C.A failure to observe Lofgren’s disease in commercial chicken populations : is not good evidence that chickens are immune to the virus that causes this : disease. : 答案是C。我想请问一下A选项是哪里不对? : 另外想请问B选项的错误之处是否是在there is no way 有过度推论之嫌? : 恳请大家帮忙解惑，谢谢! Drawn Conclusion 的题目，答案取向会比其他题型相对保守 你可以想个简单的推理，一个事件推原因，可以有许多推论解释。 但如果是拿到有限的资讯推结果，那当然相对比较无法做过多的结论。 (A) 题目完全没有 human 的资讯，所以直接删除 (B) "no symptom" ≠ "can't determine the infection" 没有 symptom 不代表无法侦测出 infection 所以此题答案不对 这是题目要考你的盲点，这个答案选项为上课时， 同学容易犯的错误陷阱选项 (C) 题目资讯为 chicken "no symptom" 是因为时间太早就上市场被吃掉 意思就是 "no symptom" ≠ "no infection" 而 (C) 就是顺着逻辑陈述 答案合理 另外，Drawn Conclusion 的确是不喜欢武断的答案， 所以 B/C 做选择时，当然是 (C) 相对好。 且 (C) 是否定极端可能性的答案，为保守性的陈述 类似答案如下题: http://www.manhattanprep.com/gmat/forums/national-budget-and-trade-deficits-t12122.html 但，武断字不能当成绝对错误的原因，如下面此题: http://gmat.kaomanfen.com/question/e50x0h.html 答案即是以 "nobody" 做开头 所以基本还是要以相关性先做判题才可 -- Donz 2015 1月全科机经班: http://ppt.cc/wwcn Donz + Keewee 四周速成实力三月班: http://ppt.cc/2oGt Donz GMAT FB: https://www.facebook.com/groups/DonzGMAT --

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