逻辑题请教20071008

your_amulet

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?

 

1. The gold content of the soil on Kodlunarn
                           Island is much lower today than it was in the sixteenth century.
2. The two mining expeditions funded by Elizabeth I did not mine the same part of Kodlunarn
                           Island.
3. The methods used to assess gold content of the soil samples provided by Frobisher were different from those generally used in the sixteenth century.
4. Frobisher did not have soil samples from any other Canadian island examined for gold content.
5. Gold was not added to the soil samples collected by Frobisher before the samples were examined.

想不通答案为什么是E,请教讲解

crazecat123

结论是说16世纪的金子测量不准，如果Frobisher有往土样本里加金子(E)，就不能说是测量方法不准了。

your_amulet

有道理,谢谢

我的问题在于结论没有搞清楚