大全-C-9

有人能解释一下这题吗，不懂

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

请问M-C是什么东东啊

m－c－9 是指费费逻辑大全的testc的第9题。

但我还是不很明白，文中说两种方法要一起用才能有效鉴定。而两种方法的必要条件是都要在土中，但b,c,d,e的选项都可以不被埋在土中。既然如此也就不会出gridding和黑面啦。

我不很清楚feather cape到底是什么，如果它是羽毛或者毛皮什么的那这个答案和别的答案最大的区别就是它的质地（不是金属或石头），但除此之外我还是不明白为什么选这答案

Because feather cape  is in vault, so has no chance to be exposed to griddding and no chance of turning red,all the other stuff is in the ground and exposed to dirt and stuff, not exposed in vault

1。utilized in combination指的是这两种标准一起结合使用(join together)，原文没说一定要两种标准都满足。只是说用这两个标准。实际是只要满足一个就行，D就是这两个都没满足

2。gridding，硬东西才能griding（刺耳的刮）

1.gridding是网格的意思， scratch 是刮的意思。地震造成很多的文物都被刮花。刺耳的声音从何而来？

2.D符合颜色这一条呀？还有一点经过地震文物都是埋在地下的，feather cape要是在地上就不用那么费劲，早被研究过了