请教GWD第13套的逻辑题

weiweifriends

Maize contains the vitamin niacin, but not in a form the body can absorb.  ellagra is a disease that results from niacin deficiency.  When maize was introduced into southern Europe from the Americas in the eighteenth century, it quickly became a dietary staple, and many Europeans who came to subsist primarily on maize developed pellagra.  ellagra was virtually unknown at that time in the Americas, however, even among people who subsisted primarily on maize.

Which of the following, if true, most helps to explain the contrasting incidence of pellagra described above?

Once introduced into southern Europe, maize became popular with landowners because of its high yields relative to other cereal crops.

Maize grown in the Americas contained more niacin than maize grown in Europe did.

Traditional ways of preparing maize in the Americas convert maize’s niacin into a nutritionally useful form.

In southern Europe many of the people who consumed maize also ate niacin-rich foods.

Before the discovery of pellagra’s link with niacin, it was widely believed that the disease was an infection that could be transmitted from person to person.

我选了E啊

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 Elizabeth 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 soil samples collected by Frobisher before the samples were examined.

我选了D，答案是E

明明D项排除了他因，可以加强啊

携隐

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lismiles

1. 玉米含维生素niacin，但其形态不能被身体吸收。Pellagra是一种由于缺乏niacin引起得疾病。当玉米在18世纪从美洲传入欧洲南部的时候，它很快成为了日常饮食的主要组成部分，但很多坚持食用玉米的欧洲人患上了pellagra。然而，pellagra完全不被美洲人甚至在那些坚持食用玉米的美洲人所知。

选C

E. 在发现pellagra与niacin有关之前，pellagra被认为是一种传染病。

并不能解释为什么欧洲人和美洲人同样吃玉米，而欧洲人缺患上pellagra。

2. 一个十六世纪的英国探险家，从k岛上取得了高金含量的土壤样本。由于高金含量被报道，elizabeth赞助了两个采矿探险队，但都没有发现金子。现代的分析指出k岛的土壤金含量很低。因此用于测定frobisher的样本金含量的方法是不准确的。

D取非  frobisher有从其他岛上取得的含金土壤样本。

而Elizabeth去的是k岛，得出低金含量的结论。用现代方法重新检测的样本和frobisher的样本完全是两种。对其他岛上的样本的检测结果可能是准确的也可能是不准确的。不能削弱结论。

E 取非 在检测之前frobisher在样本中添加了金子。说明f的样本不是原始样本，检测的结果是准确的。削弱结论。

weiweifriends

楼上的大侠，谢谢相助啊

就是还有一点不懂，Pellagra was virtually unknown at that time in the Americas........., 这里的不为美洲人所知，意思就是在美洲没有人得Pellagra这个病吗？我原以为不为所知就是美洲人也得这个病，却不知道病因是什么，不知道与玉米有关。

weiweifriends

还有，携隐大侠，小妹读了置顶帖了，惭愧惭愧，以后一定按规矩来，多谢！

lismiles

"我原以为不为所知就是美洲人也得这个病，却不知道病因是什么，不知道与玉米有关。"

如果这样理解：就不应该说“even among people who subsisted primarily on maize.”而是“even among famous doctors....."了吧？

weiweifriends

噢 有道理 楼上的大侠你考过GMAT了吗 我再过十一天考，慌啊。。。。。。

cician

答案是C，
当时做的时候，原文最后一句的这种病不被known,没理解出是患病的意思！！呜呜