雅思阅读精读练习中很重要的一个部分就是对长难句进行句型分析和翻译的练习。下面的长难句大家先自己翻译下，看看能不能翻得信达雅，然后再对照译文找差距。接下来请看雅思内容：剑桥雅思阅读精读之长难句练习
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，most geologists 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。
2、Fallois proposed that Proust had tried to begin a novel in 1908, abandoned it for what was to be a long demonstration of Saint-Beuve's blindness to the real nature of great writing , found the essay giving rise to personal memories and fictional developments ,and allowed these to take over it a steadily developing novel. F认为，P在1908年试图开始写一部小说，又为了写一部批判S-B的 伟大作品的真正本质的视而不见的长篇的证明而放弃了这部小说，其后又发现这一论文又勾起了其个人记忆及小说情节的萌生，使得后者取而代之形成了一部稳定展开的小说。
3、Granted that the presence of these elements need not argue an authorial awareness of novelistic construction comparable to that of Henry James， their presence does(15) encourage attempts to unify the novel's heterogeneous parts. 诚然，这些因素的存在并不能证明作者对小说架构的意识可与亨利。詹姆斯(Henry James)的那种意识相比拟;然则，任何力图将小说所有形形色色的因素统一起来的做法，在某种程度上注定是无法令人信服的。 Granted that:大家都统一、当然，表让步，=admitted , of course.
4、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 is topic composition of the lead from a single copper-ore source. 铅的同位素构成经常在一种普通铜矿石来源与另一种铜矿石来源之间存在差异，其差异程度超出测量误差;而最初的研究表明，对于来自单独一个铜矿石来源的铅来说，其同位素构成几乎是毫无二致的。
5、The methods that a community devises to perpetuate itself come into being to preserve aspects of the cultural legacy that that community perceives as essential. 一个社会所创造出来藉以使其自身生生不息、恒久不衰的方法得以形成产生，以保存在这个社会看来具有本质意义的文化遗产的各个方面。
以上为雅思内容：剑桥雅思阅读精读之长难句练习