The ancient Nubians inhabited an area in which typhus occurs, yet surprisingly few of their skeletons show the usual evidence of this disease.The skeletons do show deposits of tetracycline, an antibiotic produced by a bacterium common in Nubian soil.This bacterium can flourish on the dried grain used for making two staples of the Nubian diet, beer and bread.Thus, tetracycline in their food probably explains the low incidence of typhus among ancient Nubians.
Which of the following is an assumption on which the argument relies?A. Infectious diseases other than typhus to which the ancient Nubians were exposed are unaffected by tetracycline.
B. Tetracycline is not rendered ineffective as an antibiotic by exposure to the processes involved in making bread and beer.
C. Typhus cannot be transmitted by ingesting bread or beer contaminated with the infectious agents of this disease.
D. Bread and beer were the only items in the diet of the ancient Nubians which could have contained tetracycline.
E. Typhus is generally fatal.
答案是B...用的排除法，选了半天，选错了，选了C..
请大牛们指点。。-- by 会员 jessiecg (2010/9/15 15:15:55)
觉得这是挺典型的一道题
“This bacterium can flourish on the dried grain used for making two staples of the Nubian diet, beer and bread. “ 说这个细菌(跟前面一句连起来，其实也就是在说tetracycline这东西)在Nubian diet(beer and bread)很常见，”Thus, tetracycline in their food probably explains the low incidence of typhus among ancient Nubians.”推论tetracycline可抑制typhus这种疾病，问假设：
直觉就是beer and bread不会使tetracycline的效能减低
再来看答案：
A. Infectious diseases other than typhus to which the ancient Nubians were exposed are unaffected by tetracycline. (Other than跟本题无关了)
B. Tetracycline is not rendered ineffective as an antibiotic by exposure to the processes involved in making bread and beer. (取非，若tetracycline会变得没有效，那typhus的降低必然跟它无关，可以weaken结论，选它)
C. Typhus cannot be transmitted by ingesting bread or beer contaminated with the infectious agents of this disease. (typhus怎么传染跟前面都连不起来，无关)
D. Bread and beer were the only items in the diet of the ancient Nubians which could have contained tetracycline. (题目没用only，基本上这个选项可以不要看)
E. Typhus is generally fatal. (这个病会不会致死，也无关)
open to discuss
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发表于 2010-9-15 15:15:55
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