GRE阅读题目解析:青铜时代文明

　　P2

　　1

　　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.

　　了解青铜时代的文明，如何决定用来制造铜和青铜制品的铜矿石，会极大地帮助我们，了解那个时代文明间的交流和贸易。

　　2

　　Researchers have 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.

　　研究者们已经分析过这些制品和矿石中各元素的含量，但由于种种原因，这些研究大多不能为铜的来源提供证据。

　　3

　　Elemental composition can vary within the same copper-ore lode, usually because of varying admixtures of other elements, especially iron, lead, zinc, and arsenic.

　　一处矿脉中的元素构成可能有差异，通常是因为混入了不同含量的其他元素，特别是铁，铅，锌，砷。

　　4

　　And high concentrations of cobalt or zinc, noticed in some artifacts, appear in a variety of copper-ore sources.

　　而在某些制品中可以观察到，某些铜矿石来源中钴或锌的含量高。

　　5

　　Moreover, the processing of ores introduced poorly controlled changes in the concentrations of minor and trace elements in the resulting metal.

　　而且，矿石的生产工艺显示，炼制出的金属中的微量元素含量的变化无法有效控制。

　　6

　　Some elements evaporate during smelting and roasting; different temperatures and processes produce different degrees of loss.

　　有些元素在熔炼和锻造过程中蒸发;不同的温度和工艺过程造成不同程度的损耗。

　　(smelt 熔炼，把矿石炼制成金属

　　roast 煅烧矿石)

　　7

　　Finally, flux, which is sometimes added during smelting to remove waste material from the ore, could add quantities of elements to the final product.

　　最后，熔剂，熔炼过程中加入，用以从矿石中去除废料，也会在成品中混入一定量的其他元素。

　　8

　　An elemental property that is unchanged through these chemical processes is the isotopic composition of each metallic element in the ore.

　　经过这些化学工艺，一种不变的属性，是矿石中每种金属元素的同位素构成比例。

　　9

　　Isotopic composition, the percentages of the different isotopes of an element in a given sample of the element, is therefore particularly suitable as an indicator of the sources of the ore.

　　同位素构成，是某元素在一份样品中，各种同位素所占的百分比，因此，特别适合作为鉴定矿石来源的指标。

　　10

　　Of course, for this purpose it is necessary to find an element whose isotopic composition is more or less constant throughout a given ore body, but varies from one copper ore body to another or, at least, from one geographic region to another.

　　当然，为了完成测定有必要找到这样一种元素，它在一块矿石中的同位素构成比例或多或少是稳定的，但在不同矿石，或不同地域出产的矿石中，它的比例互相区别。

　　11

　　The ideal choice, when isotopic composition is used to investigate the source of copper ore, would seem to be copper itself.

　　当我们用同位素构成比例来调查铜矿石来源时，理想的选择，似乎就是铜元素本身。

　　12

　　It has been shown that small but measurable variations occur naturally in the isotopic composition of copper.

　　我们已经知道铜的同位素构成，在自然情况下，存在微小但可测量的变化。

　　13

　　However, the variations are large enough only in rare ores; between samples of the common ore minerals of copper, isotopic variations greater than the measurement error have not been found.

　　然而，这种改变只有在稀有矿石中才足够大(可测量);普通铜矿物样本的同位素差异，一般都小于测量误差。

　　14

　　An alternative choice is lead, which occurs in most copper and bronze artifacts of the Bronze Age in amounts consistent with the lead being derived from the copper ores and possibly from the fluxes.

　　另一种选择是铅，在多数青铜时代的铜以及青铜制品中都含有铅，数量大体与铜矿石中的铅相当，也可能有部分来自熔剂。

　　15

　　The isotopic composition of lead often varies from one source of common copper ore to another, with variations exceeding the measurement error; and preliminary studies indicate virtually uniform isotopic composition of the lead from a single copper-ore source.

　　不同普通铜矿石中，铅的同位素比例通常不同，这种差异超过了测量误差的范围;且初步研究显示，同一来源的铜矿样本中的铅同位素比例，实际上是一致的。

　　16

　　While some of the lead found in an artifact may have been introduced from flux or when other metals were added to the copper ore, lead so added in Bronze Age processing would usually have the same isotopic composition as the lead in the copper ore.

　　尽管有些制品中的铅可能来自于熔剂或熔炼铜矿过程中加入的其他金属，青铜时代工艺中这些被加入的铅，经常与铜矿中的铅有着相同的同位素比例。

　　17

　　Lead isotope studies may thus prove useful for interpreting the archaeological record of the Bronze Age. (473 words)

　　所以，铅的同位素研究也许能帮助我们，解读青铜时代的某些考古记录。

　　4. The author first mentions the addition of flux during smelting in the last sentence in the last paragraph in order to

　　(A) give a reason for the failure of elemental composition studies to determine ore sources

　　(B) illustrate differences between various Bronze Age civilizations

　　(C) show the need for using high smelting temperatures

　　(D) illustrate the uniformity of lead isotope composition

　　(E) explain the success of copper isotope composition analysis

　　选 A

　　我们先回头看看句 7：

　　“ Finally, flux, which is sometimes added during smelting to remove waste material from the ore, could add quantities of elements to the final product. ”

　　如果某种元素完全来自于矿石，那么可以有追踪效果。如果这种元素，也可能来自外加的物质 flux，且跟矿石中该元素的同位素构成数值差异较大，就可能干扰检测的结果，所以选 A 。

　　For the following question, consider each of the choices separately and select all that apply

　　5. According to the passage, possible sources of the lead found in a copper or bronze artifact include which of the following?

　　□A The copper ore used to manufacture the artifact

　　□B Flux added during processing of the copper ore

　　□C Other metal added during processing of the copper ore

　　选 ABC

　　句 16：

　　While some of the lead found in an artifact may have been introduced from flux or when other metals were added to the copper ore, lead so added in Bronze Age processing would usually have the same isotopic composition as the lead in the copper ore.

　　铜矿石中都含有铅，句 16 告诉我们熔炼过程中加入熔剂和其他金属，也可能带入了铅，所以选 ABC 。

　　6. Select the sentence in the passage that the author rejects copper as the “ideal choice” .

　　句13

　　“However, the variations are large enough only in rare ores; between samples of the common ore minerals of copper, isotopic variations greater than the measurement error have not been found. ”

　　我们要测量某种差异，测量过程中也一定会发生误差，只有当这种差异在相当程度上超过误差的规模时，我们才能采信这种结果。

　　比如我要回忆我跟我小学同桌的学习程度的对比，回忆的对象是期末考试分数，回忆可能存在几分偏差。

　　假设我同桌学习特棒总是95左右，那么算上误差她可能90-100分，而我一般都是75，算上误差也不会到80以上，则这种对比是有明确结果的。

　　如果我们都是80分左右，则我的回忆完全不能比较我们的程度差异，也许我们该换一种方式，比如回母校查阅当年考试成绩的记录。

　　7. It can be inferred from the passage that the use of flux in processing copper ore can alter the lead isotope composition of the resulting metal EXCEPT when

　　(A) there is a smaller concentration of lead in the flux than in the copper ore

　　(B) the concentration of lead in the flux is equivalent to that of the lead in the ore

　　(C) some of the lead in the flux evaporates during processing

　　(D) any lead in the flux has the same isotopic composition as the lead in the ore

　　(E) other metals are added during processing

　　选 D

　　逻辑题。

　　从第 4 题，我们知道，要确定铜，科学家分析铅，但是铅可能有外来一些干扰，题目问我们哪种情况下可以排除这种干扰，注意 EXCEPT 。

　　如果加入的铅在同位素构成比例上，和矿石中原有的铅相同，加多少也就无所谓，因为我要测的是同位素的衰减程度。

　　举个类比的例子，比如我们跟踪研究一些现在 80 岁左右的老头，如果 60 年前混入我们研究范围的几个男青年恰好都是 20 岁，那么现在他们也 80 岁了，不会影响我们调查 80 岁老头的结果。

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