Q16:

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?

The gold content of the soil on Kodlunarn Island is much lower today than it was in the sixteenth century.

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

I could not understand the meaning.

F从K岛弄的土含有大量黄金。因为有这个报告，E开始挖，但什么都没弄到。现在的分析发现，岛上的土含有很少的黄金。所以，F用的测量方法有问题。

问assumption，没有其他原因；

Which of the following is an assumption on which the argument depends?