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编辑点评： GRE阅读的复习和作文的复习往往可以相辅相成，这里为大家精选了一些阅读中的句子，大家可以选择性地用在作文中作为一个例证。也可以参考句子的结构自己学着写一下结构较为复杂的句子。 40.It is possible to make specific complementary DNA sthat can serve as molecular probes to seek out the messengerRNA s of the peptide hormones. If brain cells are making thehormones，the cells will contain these Mrna S. If the products the braincells make resemble the hormones but are not identical to them，then thecDNA s should still bind to these mRNA s，but should not bind astightly as they would to mRNA s for the true hormones. 科学家可以制造出特异的互补DNA s，以此作为分子探子，探觅出肽激素的信使RNA 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。 41.The molecular approach to detecting peptide hormones using cDNAprobes should also be much faster than the immunological method becauseit can take years of tedious purifications to isolate peptide hormonesand then develop antiserums to them. | 
