89.  由于空间不足，艺术博物馆在考虑购买和接受捐赠的艺术品是越来越慎重，有些情况下放弃其进一步改善收藏的机会。

90.  美国宪法要求总统是生于美国本土的公民，三十五岁以上，并且在美国居住了至少十四年。

91.  美国西部的不毛之地正成为玩耍的地方，对越来越多拥有摩托车或越野单车类车辆的，喜欢放纵于爬坡比赛或开辟新的沙漠通道的寻欢作乐者具有不断增长的吸引力。

92.  石头不会腐烂，所以以前的(石器)工具能保存下来，虽然它们的制造者已经消失的无影无踪。

93.  昆虫就将会使我们无法在这个世界上居住；如果我们没有受到以昆虫为食的动物的保护，昆虫就会吞嚼掉我们所有的庄稼并杀死我们饲养的禽兽。

94.  确实，他们在探险中遇到了极具威胁性的困难和危险，而他们的装备会让一个现代登山者想一想都会浑身颤栗。不过他们并不是刻意去追求刺激的。

95.  老人和年轻人之间只有一个区别：年轻人的前面有辉煌的未来，老年人灿烂的未来却已在它们身后。这也许就是困难之所在。

96.  我们位年强人振奋。它们带有自由的气息，他们不会为狭隘的野心和贪婪享受而孜孜以求。他们不是焦虑的向上爬的人，他们不会对物质性的东西难舍难分。

97.  每次我听说体育运动能够在国家间建立起友好感情，说世界各地的普通人只要能在足球场或板球场上相遇就会没有兴趣在战场上相遇的话，我都倍感诧异。

98.  没有可能仅仅为了娱乐或锻炼而运动：一旦有了问题，一旦你觉得你输了你和你所属团体会有失体面时，你最野蛮的好斗本能就会被激发出来。

 99.  人们已经发现，某些蝙蝠发出尖叫声并靠接受回响来锁定和避免障碍物——或者找到它们赖以为生的昆虫。蝙蝠这种回响定位法常拿来和原理与之很相近似的雷达相比。

100. 随着芯片制造时间和费用降低到了几天和几百美元，工程师们可能很快可以任他们的想象驰骋而不会被昂贵的失败所惩罚。

42.The wallflower is so called because its weak stems often grow on walls and along stony cliffs for support.

　　43. It is the interaction between people, rather than the events that occur in their lives, that is the main focus of social psychology.

　　44. No social crusade aroused Elizabeth Williams’enthusiasm more than the expansion of educational facilities for immigrants to the United States.

　　45. Quails typically have short rounded wings that enable them to springsintosfull flight instantly when disturbed in their hiding places.

　　46. According to anthropologists, the earliest ancestors of humans that stood upright resembled chimpanzees facially, with sloping foreheads and protruding brows.

　　47. Not until 1866 was the fully successful transatlantic cable finally laid.

　　48. In his writing, John Crowe Ransom describes what he considers the spiritual barrenness of society brought about by science and technology.

　　49. Children with parents whose guidance is firm, consistent, and rational are inclined to possess high levels of self-confidence.

　　50. The ancient Hopewell people of North America probably cultivated corn and other crops, but hunting and gathering were still of critical importance in their economy.

　　51. Using many symbols makes it possible to put a large amount of information on a single map.

　　52. Anarchism is a term describing a cluster of doctrines and attitudes whose principle uniting feature is the belief that government is both harmful and unnecessary.