教你分析GRE阅读文章篇章结构

从词、句、结构的角度GRE阅读段是最有效也是最有收获的一种方式，有利于大家增强长难句的分析能力，积累词汇，写作素材以及作文结构构架方法。下面我们就拿GRE阅读NO题的8-1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。

我们从词--句--篇章来谈谈这篇文章。

原文：

Geologists have long known that the Earths mantle is heterogeneous， but its spatial arrangement remains unresolvedis 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 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 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.