众所周知大家对GRE、GMAT的阅读理解，必须使用结构化的巡读法进行，效率高，收效高，因为GRE以及GMAT阅读理解的规律性是非常强，同时我们阅读是阅读其文章的逻辑，因此是用逻辑思维操作逻辑阅读，但是我们也要知道能做对阅读题目的同时，我们也要通过每一篇GRE、GMAT阅读文章来强化训练自己实实在在的阅读能力，例如：长难句的分析能力、词汇的积累，写作素材的积累、以及写作结构的掌握。可以说，每一篇GRE阅读理解都是我们备考GRE、GMAT写作的Issue部分的最好的素材库以及范文展示，现在，我们本文来源:考试大网拿GRE阅读NO题的NO8-1这篇文章做一个示范，来说明一下除了我们做对每一个阅读选择题以外，我们应该从阅读文章中获得些什么资源，提炼一个文章的哪些“语言要素”有助于英语能力的提高、GRE/GMAT写作能力的提高，而不只是应试阅读能力的提高。

NO8-1，我们从“词--句--篇章”来谈谈这篇文章。
　　
原文：
Geologists have long known that the Earth’s mantle is heterogeneous, but its spatial arrangement remains unresolved—is the mantle essentially layered or irregularly heterogeneous? The best evidence for the layered-mantle thesis is the well-established fact that volcanic rocks found on oceanic islands, islands believed to result from mantle plumes arising from the lower mantle,are composed of material fundamentally different from that of the midocean ridge system, whose source, most geologists contend, is the upper mantle.Some geologists, however, on the basis of observations concerning mantle xenoliths, argue that the mantle is not layered, but that heterogeneity is created by fluids rich in "incompatible elements" (elements tending toward liquid rather than solid state) percolating upward and transforming portions of the upper mantle irregularly, according to the vagaries of the fluids’ pathways. We believe, perhaps unimaginatively, that this debate can be resolved through further study, and that the underexplored midocean ridge system is the key.

　　
一、难词
spatial: a.1.空间的，太空的；2.存在(或者发生)于宇宙空间的
plume: n.1.羽状物2.柱，地柱
xenolith:俘虏岩
percolate:v.1.渗透2.扩散到，弥漫于
portions: n.一部分

　　
二、难句
1.the best evidence for the layered-mantle thesis is the well-established fact that volcanic rocks found on oceanic islands，islands believed to result from mantle plumes arising from the lower mantle，are composed of material fundamentally different from that of the mid-ocean ridge system， whose source，mostgeologists contend，is the upper mantle.
对于地幔分层论点来说，最好的证据乃这样一个确认的事实，即在那些海洋岛屿——这些岛屿据信是源于由下层地幔升上来的地幔柱状溶岩流(mantle plume)——上发现的火山岩石，是由与海洋中部山脊系统的物质根本不同的物质构成的，而这一海洋中部山脊系统的成因，大多数地质学家论辩道，为上部地幔。