标题: 求教prep cr 118 [打印本页] 作者: cherryfane 时间: 2010-8-16 22:09 标题: 求教prep cr 118 Theancient Nubians inhabited an area in which typhus occurs, yet surprisingly fewof their skeletons show the usual evidence of this disease. The skeletons do show deposits oftetracycline, an antibiotic produced by a bacterium common in Nubian soil. This bacterium can flourish on the driedgrain used for making two staples of the Nubian diet, beer and bread. Thus, tetracycline in their food probablyexplains the low incidence of typhus among ancient Nubians. Whichof the following is an assumption on which the argument relies? A.Infectious diseases other than typhus to which the ancient Nubians were exposedare unaffected by tetracycline. B.Tetracycline is not rendered ineffective as an antibiotic by exposure to theprocesses involved in making bread and beer. C.Typhus cannot be transmitted by ingesting bread or beer contaminated with theinfectious agents of this disease. D.Bread and beer were the only items in the diet of the ancient Nubians whichcould have contained tetracycline. E.Typhus is generally fatal. 答案是 B 这个题好复杂 看晕了 我选了C 求大家解答~~作者: jessiecg 时间: 2010-9-12 15:41
UP~ 求大牛们给讲一下啊 我也选的C作者: Lambton 时间: 2010-9-12 16:00
这题属于A推B。A可行，A有意义的类型。
A：tetracycline 是一种produced by a bacterium common in Nubian soil 的抗体。 B：作者结论：正是由于这种抗体tetracycline，才使得the low incidence of typhus among ancient Nubians（才使得typhus这种病的发生率低）
所以tetracycline 一定要可行才行。
而题中说This bacterium can flourish on the driedgrain used for making two staples of the Nubian diet, beer and bread. 也就是说Nubians是通过摄入beer和bread来得到这种抗体tetracycline 的。