[求助]请教两道逻辑题

liusiming

Archaeologists seeking the location of a legendary siege and destruction of a city are excavating

In several possible place, including a middle and a lower layer of a large mound. The bottom of the middle layer contains some pieces of pottery of type 3, known to be form a later period than the time of the destruction of the city, but the lower layer does not.

 

 

19.Which of the following hypothesis is best support by the evidence above?

A.      The lower layer contains the remains of the city where the siege took place.

B.      The legend confuses stories from two different historical periods.

C.      The middle layer does not represent the period of the siege

D.      The siege lasted for a long time before the city was destroyed

E.       The pottery of type 3 was imported to the city by traders

 

 

20.The force of the evidence cited above is most seriously weakened if which of the following is true?

A.      Gerbils, small animals long native to the area, dig large burrows into which objects can fall when the burrow collapse

B.      Pottery of types 1 and 2, found in the lower level, was used in the cities from which, according to the legend, the besieging forces came.

C.      Several pieces of stone from a lower-layer wall have been found incorporate into the remains of a building in the middle layer.

D.      Both the middle and the lower layer show evidence of large-scale destruction of habitation by fire

E.       Bronze axheads of a type used at the time of the siege were found in the lower level of

Excavation

答案分别是C和A  请教详细解题思路  19题为什么A不正确呢？

 

isi

第一题，

常识：1.埋得越low的layer，时间上越古老，越浅的越接近现在时点

      2.siege肯定发生在城市毁灭之前

pottery of type 3, known to be form a later period than the time of the destruction of the city可以知道这些陶器出现时间在城市毁灭之后，

The bottom of the middle layer contains some pieces of pottery of type 3由常识2可知，这些破罐子存在于middle layer 的时间之前

故middle layer中的东西一定是在城市毁灭之后，由常识2可以得出c答案。

从正文中找不到证据证明the lower layer代表的是siege的时点，只能知道destruction of the city有可能发生在the lower layer。

第二道题，weaken方式为unermine题干前提的有效性。

实际上是质疑我在第一题里提到的常识1，这个常识是下文推理的assumption，削弱assumption结论就无法成立，故起到weaken作用。

自己表达不好，希望可以帮到你理解。

liusiming

非常感谢，好像明白了