难题II

9.       Determining the authenticity of purported pre-Columbian artifacts is never easy. Carbon-14 dating of these artifacts is often impossible due to contamination by radioactive palladium (which occurs naturally in the soils of Central and South America). However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts. First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding. In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas.

The criteria above would be LEAST useful in judging the authenticity of which of the following?

(A) An ax head of black obsidian, unearthed from a kitchen midden

(B) A pottery bowl with a red ocher design, found in the ruins of a temple

(C) A set of gold ear weights, ornamented with jasper pendants

(D) A black feather cape from a king’s burial vault（D）

(E) A multicolored woven sash found near the gravesite of a slave

为什么选 D呢？

文章都难看太懂

UP

首先搞明白文章什么主旨。应该是再说考古学的鉴定、检测方法。

Determining the authenticity of purported pre-Columbian artifacts is never easy. Carbon-14 dating of these artifacts is often impossible due to contamination by radioactive palladium (which occurs naturally in the soils of Central and South America).以上提出了，传统的碳-14法（常用的考古学年代测定法）不好使，因为有杂质的干扰。 However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts.以上一句说找到一种二合一标准使鉴定可以很有效。以下介绍这两个标准 First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding. 1、因为震荡产生了独特的网状磨损痕迹In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas另外就是颜色，因为常年的土壤中的化学成分侵蚀。使颜色变暗。

再看题，说上述2合1标准对下面哪个文物鉴定不好使！上面的标准是通过独特网状磨损和发暗的颜色来判断。所以哪个使这两个特点不好使就是哪个！D中黑色的羽毛肯定是首选，你看不出暗色也辩不出哪门子磨损网纹！

高人再指正吧，我到头就这水平了！

问题就是为什么不选A

that's it 5 lou !

两个条件必须都不满足！我是这样理解的，再请高人来看看吧！