杨鹏GRE阅读难句背诵100例[8]

36.Most striking among the many asymmetries evident in an adult flatfish is eye placement： before maturity one eye migrates，so that in an adult flatfish both eyes are on the same side of the head.

在一条成年比目鱼身上显著存在的诸多不对称（asymmetry）特征中，最为吸人注目的是眼睛的摆位：在成年之前，一只眼睛发生移动，因此在成年比目鱼身上，两只眼睛均位于头部的同一侧面。

37.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.

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。

38.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.

但是，某些地质学家，以对地幔捕虏岩体（xenolith）所作的观察为依据，指出地幔并非是分层排列的，相反，地幔的异质性是由那些富含“不相容成分”的流质构成的，这些成分趋向于流体而非固体的状态，自下而上渗透扩散，并依照这些流质流向的任意性，不规则地将上部地幔的某些部分予以改变。

39.The very richness and complexity of the　meaningful relationships that kept　presenting and rearranging themselves　on all levels，from abstract intelligence to profound dreamy feelings， made it difficult for Proust to set them out coherently.

各种有意义的联系在所有的层次上，自抽象的理性至深刻的梦幻般的情感，层出不穷并不断重新组合排列；正是这些有意义的联系的丰富性和复杂性，致使普鲁斯特难于将它们错落有致地安排好。

40.It is possible to make specific complementary DNA’s （cDNA’s）that can serve as molecular probes to seek out the messenger RNA’s （mRNA’s）of the peptide hormones. If brain cells are making the hormones，the cells will contain these Mrna’S. If the products the brain cells make resemble the hormones but are not identical to them，then the cDNA’s should still bind tothese mRNA’s，but should not bind as tightly as they would to mRNA’s for the true hormones.

科学家可以制造出特异的（specific）互补DNA’s（cDNA’s），以此作为分子探子（molecular probe），探觅出肽激素的信使RNA’s（mRNA’s）。如果大脑正在制造着肽激素，则细胞就会含有这些信使RNA’s.假若细胞所制造的产品类似于肽激素但并非与这些肽激素全然相同，那么，互补cDNA’s应仍然和这些信使mDNA’s粘结的程度。含有这些mRNA’s的脑细胞然后就可以被分离开来，研究者可对其信使RNA’s进行解码，以确定它们的蛋白质产品究竟是什么，并确定这些蛋白质产品在何种程度上类似于真正的肽激素。