81. The American clipper ship era was of duration short, extending from about 1845 to 1859. 答案：B 分析及考点：词序的颠倒，应该改成short duration.只有特殊情况修饰成分后置。 参考译文：美国的剪帆船的时期经历时间很短，只有从1845到1859. 82. Crystals of pure quartz, usually called rock crystal, are coarseness, colorless, and transparent. 答案：D 分析及考点：平行对称结构，词性不对称，所以coarseness名词应改成coarse 参考译文：纯净石英的结晶，通常称为岩石水晶，是粗糙的，无色的，透明的。 83. Of 120 minerals known to have been used as gemstones, only about 25 are in common use in today jewelry. 答案：D 分析及考点：词序的问题。应该改成jewelry today. 参考译文：在作为宝石使用的所知道的120种矿石中，只有25种是现在珠宝业通常使用的。 84. One of the thirteen original state of the United States, North Carolina lies on the Atlantic coast midway between New York and Florida. 答案：A 分析及考点：名词单复数使用错误。应该用复数states.看到one of the. 参考译文：北卡罗来那州是最初组成美国的13个州中的一个座落在大西洋岸边，在纽约州和佛罗里达州的中间。 85. The various peoples who developed North America have made it a world leader economic . 答案：D 分析及考点：词序的颠倒。改成economic leader 参考译文：发展北美的多个民族把北美建设成了全世界的经济领袖。 86. The Milky Way is a flat spiral galaxy who contains an estimated 100 billion stars, including the Sun. 答案：B 分析及考点：定语从句连接词的误用，应改为which 参考译文：银河系是一个扁平的螺旋星系，它包含有估计100亿颗恒星，包括太阳。 87. The piano as it is known today represents a long series of experiments extend back to the year 1711, or perhaps even earlier. 答案：C 分析及考点：词性误用。应该改成extending. 参考译文：今天所知的钢琴代表了一系列的实践，一直可以追溯到1711，或者更早。 88. Climate is the primarily force that distinguishes one biome, or major terrestrial region, from another. 答案：B 分析及考点：词性误用，修饰名词用形容词，所以改成primary 参考译文：气候是一个主要的因素来区分生物群或者主要陆地相互之间的不同。 89. Prehistoric villagers tended to work harder, suffer from more diseases, and eat the poorer diet than nomadic hunters did. 答案：D 分析及考点：冠词误用。比较级前不用加定冠词the，直接用poorer diet就行 参考译文：史前的村民们倾向于努力工作，防除疾病，和吃比游牧的猎人少的食物。 90. A major Canadian city, Montreal is second only to Paris as the most largest French-speaking city in the world. 答案：D 分析及考点：最高级表述有误。Largest已经是最高级了，前面不用再加most 参考译文：加拿大主要的城市蒙特利尔，是世界上仅次于巴黎的第二最大法语城市。