一道prep逻辑题~

stevenH

Archaeologists in Michigan have excavated a Native American camp near Dumaw Creek. Radiocarbon dating of animal bones found at the site indicates that the camp dates from some time between 1605 and 1755. However, the camp probably dates to no later than 1630, since no European trade goods were found at the site, and European traders were active in the region from the 1620's onward.

Which of the following, if true, most strengthens the argument?

• ADue to trade among Native Americans, some European trade goods would have reached the area before the European traders themselves did.  
• BAt all camps in the region that have been reliably dated to the late 1620's, remains of European trade goods have been found.  
• CThe first European trade goods to reach the area would have been considered especially valuable and preserved as much as possible from loss or destruction.  
• DThe first European traders in the area followed soon after the first European explorers.  
• EThe site is that of a temporary camp that would have been used seasonally for a few years and then abandoned.  
  

答案是B。想问一下A咋不对啊。。文中说欧洲贸易是在1620‘s，现在又说有些贸易品在这之前就在这地方出现了，而这个camp并没有发现这些remains，说明这个camp在更之前啊，就加强了结论？

Junwalker

我觉得主题句是however后面的the camp probably dates to no later than 1630，也就是说这个营地应该是在1630年以前就有了的，下面选项里面能够证明这个营地是1630年以前的，换句话说和年份有关的只有B了。

stevenH

A选项虽然没有具体说年份，但也是跟时间有关啊

alzn2765

逻辑是：前提（因）欧洲贸易商1620年末就活跃在这里了并且site没有发现欧洲贸易商留下的贸易商品
结论（果）这个site不晚于1630年

从因到果有一个gap，或者漏洞：如果欧洲贸易商即使活跃在这个地区也从不在任何site留下任何贸易商品呢？结论显然就无法成立了。我甚至可以说这个site是1755年的也可以。
而B选项就是正好填补这个gap或者堵住这个漏洞：在确认到1620年代末的site里，都发现了欧洲贸易商留下的贸易商品。也就是说从至少从1620年代末开始，欧洲贸易商都开始留下点儿什么了。这样就把1630年以后的时间都给否定了。

这题其实是一道assumption题，加强其实就是找填补gap的conditional premise。

我微信alzn2765，欢迎问题，大家共同进步。

AnnAys

alzn2765 发表于 2015-8-5 23:55
逻辑是：前提（因）欧洲贸易商1620年末就活跃在这里了并且site没有发现欧洲贸易商留下的贸易商品
结论（果 ...

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