雅思长难句一直是雅思阅读高分的拦路虎，同学们需要学会层次分析法，将长句子拆分开来，就好理解多了哦。希望以下内容能够对大家的雅思学习有所帮助！

56. Now we must also examine the culture as we Mexican Americans have experienced it , passing from a sovereign people to compatriots with newly arriving settlers to , finally ，a conquered people - a charter minority on our own land.

现在我们必须也按照我们墨西哥裔的美国人的经历来审视这个文化，我们的经历是从一个主权的民族变成了新来的定居者的同胞，在最终沦落成为一个被征服的民族——在我们自己的土地上的契约的少数民族。

57. 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 to these 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。

58. The molecular approach to detecting peptide hormones using cDNA probes should also be much faster than the immunological method because it can take years of tedious purifications to isolate peptide hormones and then develop antiserums to them. 采用cDNA探子来测定肽激素的这一分子生物学方法同时也应该比免疫学的方法速度来得快，因为对于免疫的方法来说，需耗费好几年枯燥的提纯进程，方能将肽素分离了出来，然后再培养出针对它们的抗血清。

59. Nevertheless, researchers of the Pleistocene epoch have developed all sorts of more or less fanciful model schemes of how they would have arranged the Ice Age had they been in charge of events.

然而，研究P时代的研究者发展除了各种各样的或多或少有些奇怪思想的模型系统，用来显示如果由他们来决定地质事件的话他们将会如何安排冰川纪。

60. This succession was based primarily on a series of deposits and events not directly related to glacial and interglacial periods，rather than on the more usual modern method of studying biological remains found in interglacial beds themselves interstratified within glacial deposits.

这一序列演替(succession)所依据的，主要是一系列与冰川期和间冰期并不直接相关的地质沉积物和地质事件，而不是依据更为普遍的现代方法，去研究间冰层(interglacial bed)中所发现的生物残留物，而这些间冰层本身又在冰川沉积物发生间层化(interstatified)。

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