36. The historian Frederick J. Turner wrote in the 1890’s that the agrarian discontent that had been developing　steadily in the United States since about 1870 had been precipitated by the　　closing of the internal frontier——that is, the depletion of available new land　needed for further expansion of the American farming system.

史学家弗雷德里克.杰.特纳（Frederick J.Turner）于十九世纪九十年代著述道，美国约自18世纪70年代以来一直在持续不断发展的农民不满，由于国内边远地区（internal frontier）的封闭而更趋加剧——亦即是说，美国农业系统进一步扩展所必需的可资利用的新土地几近耗竭。

37. In the early 1950’s，historians who studied preindustrial Europe （which we may define here as Europe in the period from roughly 1300 to 1800） began， for the first time in large numbers, to　　investigate more of the preindustrial European population than the 2 or 3 percent who comprised the political　and social elite: the kings, generals, judges, nobles, bishops, and local　magnates who had hitherto usually filled history books.

难句类型：复杂修饰、插入语

译文：二十世纪五十年代早期，研究前工业化时代欧洲（此处我们可将其界定为约自1300年至1800年这一时期的欧洲）的史学家，首次以众多的人数（杨鹏的书中：第一次以大量的数据），开始调查前工业化时代欧洲人口中的大多数，而非那些构成了政治与社会精英阶层的百分之二或三的人口，即国王、将军、法官、贵族、主教、以及地方上的达官显贵，而正是这部分人一直到那时为止普遍充斥于史学著作。

38. Even the requirement that biomaterials processed from these materials be nontoxic to host tissue can be met by techniques derived from studying the reactions of tissue cultures to biomaterials or from short-term implants.

即使是这样的要求，即从这些材料中加工出来的生物材料应该对受移植者的组织无害，也能够通过从研究组织培养对生物材料的反应而来的，或从研究短期移植而来的技术来满足。

39. But achieving necessary matches in physical properties across interfaces between living and　　nonliving matter requires knowledge of which molecules control the bonding of cells to each other—an area that we have not yet explored thoroughly.

但是，要想沿着原生和非原生物质之间的界面获取生理特性的必要匹配，需要某种知识，即什幺样的分子控制着细胞彼此间的结合——而对这一领域，我们尚未进行充分的探索。

40. Islamic law is a phenomenon so different from all other forms of law—notwithstanding, of course, a　considerable and inevitable number of coincidences with one or the other of them as far as subject matter and positive enactments are concerned—that its study is indispensable in order to　appreciate adequately the full range of　possible legal phenomena.

伊斯兰法是一种如此不同于所有其它法律形式的现象——毋庸置疑，尽管就其主要内容和有积极意义的法规而言，与其它法律形式中的这种或那种形式存在着相当数量的且不可避免的巧合相似之处——以致于对它进行研究便显得不可或缺，以便充分理解有可能存在的法律现象的全部范围。