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

译文：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。

难句类型：复杂修饰

解释：典型的句子套句子。主句是F.J.T. wrote that，宾语从句中主干是the agrarian discontent hadbeen precipitated by the closing of the internal frontier，在从句的主语the agrariandiscontent后面又来了一个定语从句。

意群训练：The historian Frederick J. Turner wrote in the 1890’s that the agrarian discontentthat had been developing　steadily in the United States 　since about 1870 had beenprecipitated by the closing of the internal frontier——that is，the depletion of available newland　needed for further expansion of the American farming system.

2. In the early 1950’s，historians who studied preindustrial Europe （which we maydefine here as Europe in the period from roughly 1300 to 1800） began， for the firsttime in large numbers，to investigate more of the preindustrial European populationthan the 2 or 3 percent who comprised the political　and social elite：thekings，generals，judges，nobles，bishops，and local　magnates who had hithertousually 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。

解释：句子中有两个插入语，一个是跟在preindustrial Europe之后的which we may define here asEurope in the period from roughly 1300 to 1800,这个插入语的直接作用是解释前面的preindustrialEurope的年代，而起到的客观作用则是把主句中的主语和谓语分割得很远；第二个插入语是在began，forthe first time in large numbers, to investingate中间，把一个好好的began to斩为两段。 这句话另外一个难以理解的地方是more of the preindustrial European population than the 2 or 3 percent，表示的是在工业化以前的欧洲人口中超过了那2%到3%的人，亦即占97%到98%的人民群众。

　　

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