|
新gre考试实施以来，参加了新版gre考试的考生都觉得阅读部分的题难度增加了，这主要是由于新gre考试逻辑阅读需要考生的逻辑反应一定要比以前更快，可能考生还是有点不习惯，或是没有准备充足。那么，接下来的几天，小编将给大家搜索整理一些新gre考试逻辑阅读的练习题，希望考生能从平日的练习中总结规律，找到解题技巧。 The determination of the sources of copper ore used in the manufacture of copper and bronze artifacts of Bronze Age civilizations would add greatly to our knowledge of cultural contacts and trade in that era. Researchers have 5 analyzed artifacts and ores for their concentrations of elements, but for a variety of reasons, these studies have generally failed to provide evidence of the sources of the copper used in the objects. Elemental composition can vary within the same copper-ore lode, usually because of varying admixtures of 10 other elements, especially iron, lead, zinc, and arsenic. And high concentrations of cobalt or zinc, noticed in some artifacts,appear in a variety of copper-ore sources. Moreover, the processing of ores introduced poorly controlled changes in the concentrations of minor and trace elements in the 15 resulting metal. Some elements evaporate during smelting and roasting; different temperatures and processes produce different degrees of loss. Finally, flux, which is sometimes added during smelting to remove waste material from the ore, could add quantities of elements to the final product. | 
