76. The beaver chews down trees to get food and material with which to build its home.

76.水獺啃倒樹木，以便取食物并獲得造窩的材料。

77. Poodles were once used as retrievers in duck hunting, but the American Kennel Club does not consider them sporting dogs because they are now primarily kept as pets.

77.長卷毛狗曾被用作獵鴨時叼回獵物的獵犬，但是美國Kennel Club卻不承認它們為獵犬，因為它們現在大多數作為寵物飼養。

78. As a result of what is now know in physics and chemistry, scientists have been able to make important discoveries in biology and medicine.

78.物理學和化學的一個成果是使得科學家們能在生物學和醫學上獲得重大發現。

79. The practice of making excellent films based on rather obscure novels has been going on so long in the United States as to constitute a tradition.

79.根據默默無聞的小說制作優秀影片在美國由來已久，已經成為傳統。

80. Since the consumer considers the best fruit to be that which is the most attractive, the grower must provide products that satisfy the discerning eye.

80.因為顧客認為最好的水果應該看起來也是最漂亮的，所以種植者必須提供能滿足挑剔眼光的產品。

81. Television the most pervasive and persuasive of modern technologies, marked by rapid change and growth, is moving into a new era, an era of extraordinary sophistication and versatility, which promises to reshape our lives and our world.

81.電視，這項從迅速變化和成長為標志的最普及和最有影響力的現代技術，正在步入一個新時代，一個極為成熟和多樣化的時代，這將重塑我們的生活和世界。

82. Television is more than just an electronics; it is a means of expression, as well as a vehicle for communication, and as such becomes a powerful tool for reaching other human beings.
82.電視不僅僅是一件電器；它是表達的手段和交流的載體并因此成為聯系他人的有力工具。
83. Even more shocking is the fact that the number and rate of imprisonment have more than doubled over the past twenty years, and recidivism------that is the rate for re-arrest------is more than 60 percent.
83.更讓人吃驚的事實是監禁的數目和比例在過去的二十年中翻了一番還有余，以及累犯率——即再次拘押的比例——為百分之六十強。

84.William Rainey Harper lured him to the new university of Chicago, where he remained officially for exactly a generation and where his students in advanced composition found him terrifyingly frigid in the classroom but sympathetic and understanding in their personal conferences.

84.他的教書生涯始于麻省理工學院，但是William Rainey Harper把他吸引到了新成立的芝加哥大學。他在那里正式任職長達整整一代人的時間。他的高級作文課上的學生覺得他在課上古板得可怕，但私下交流卻富有同情和理解。

85. The sloth pays such little attention to its personal hygiene that green algae grow on its coarse hair and communities of a parasitic moth live in the depths of its coat producing caterpillars which graze on its mouldy hair. Its muscles are such that it is quits incapable of moving at a speed of over a kilometer an hour even over the shortest distances and the swiftest movement it can make is a sweep of its hooked arm.

85.樹獺極不講究衛生，以至于它粗糙的毛發上生出綠苔，成群的寄生蛾生長在它的皮毛深處，變成毛毛蟲，并以它的臟毛為食。她的肌肉不能讓他哪怕在很短的距離以內以每小時一公里的速度移動。它能做的最敏捷的動作就是揮一揮它彎曲的胳膊。

86. Artificial flowers are used for scientific as well as for decorative purposes. They are made from a variety of materials, such as way and glass, so skillfully that they can scarcely be distinguished from natural flowers.

86.人造花卉即可用于科學目的，也可用于裝飾目的，它們可以用各種各樣的材料制成，臂如蠟和玻璃；其制作如此精巧，幾乎可以以假亂真。

87. Three years of research at an abandoned coal mine in Argonne, Illinois, have resulted in findings that scientists believe can help reclaim thousands of mine disposal sites that scar the coal-rich regions of the United States.

87.在伊利諾州Angonne市的一個廢棄煤礦的三年研究取得了成果，科學家們相信這些成果可以幫助改造把美國產煤區弄得傷痕累累的數千個舊煤場。

88. When the persuading and the planning for the western railroads had finally been completed, the really challenging task remained: the dangerous, sweaty, backbreaking, brawling business of actually building the lines.

88.當有關西部鐵路的說服和規劃工作終于完成后，真正艱難的任務還沒有開始；即危險，吃力，需要傷筋動骨和吵吵嚷嚷的建造這些鐵路的實際工作。

89. Because of the space crunch, the Art Museum has become increasingly cautious in considering acquisitions and donations of art, in some cases passing up opportunities to strengthen is collections.

89.由于空間不足，藝術博物館在考慮購買和接受捐贈的藝術品是越來越慎重，有些情況下放棄其進一步改善收藏的機會。

90. The United States Constitution requires that President be a natural-born citizen, thirty-five years of age or older, who has lived in the United States for a minimum of fourteen years.

90.美國憲法要求總統是生于美國本土的公民，三十五歲以上，并且在美國居住了至少十四年。

91. Arid regions in the southwestern United States have become increasingly inviting playgrounds for the growing number of recreation seekers who own vehicles such as motorcycles or powered trail bikes and indulge in hill-climbing contests or in caving new trails in the desert.

91.美國西部的不毛之地正成為玩耍的地方，對越來越多擁有摩托車或越野單車類車輛的，喜歡放縱于爬坡比賽或開辟新的沙漠通道的尋歡作樂者具有不斷增長的吸引力。

92. Stone does decay, and so tools of long ago have remained when even the bones of the man who made them have disappeared without trace.

92.石頭不會腐爛，所以以前的(石器)工具能保存下來，雖然它們的制造者已經消失的無影無蹤。

93. Insects would make it impossible for us to live in the world; they would devour all our crops and kill our flocks and herds, if it were not for the protection we get from insect-eating animals.

93.昆蟲就將會使我們無法在這個世界上居住；如果我們沒有受到以昆蟲為食的動物的保護，昆蟲就會吞嚼掉我們所有的莊稼并殺死我們飼養的禽獸。

94. It is true that during their explorations they often faced difficulties and dangers of the most perilous nature, equipped in a manner which would make a modern climber shudder at the thought, but they did not go out of their way to court such excitement.

94.確實，他們在探險中遇到了極具威脅性的困難和危險，而他們的裝備會讓一個現代登山者想一想都會渾身顫栗。不過他們并不是刻意去追求刺激的。

95. There is only one difference between an old man and a young one: the young man has a glorious future before him and old one has a splendid future behind him: and maybe that is where the rub is.

95.老人和年輕人之間只有一個區別：年輕人的前面有輝煌的未來，老年人燦爛的未來卻已在它們身后。這也許就是困難之所在。

96. I find young people exciting. They have an air of freedom, and they have not a dreary commitment to mean ambitions or love comfort. They are not anxious social climbers, and they have no devotion to material things.

96.我被年輕人振奮。他們帶有自由的氣息，他們不會為狹隘的野心和貪婪享受而孜孜以求。他們不是殫精竭慮地向上爬的人，他們不會對物質性的東西難舍難分。

97. I am always amazed when I hear people saying that sport creates goodwill between the nations, and that if only the common peoples of the world could meet one another at football or cricket, they would have no inclination to meet on the battlefield.

97.每次我聽說體育運動能夠在國家間建立起友好感情，說世界各地的普通人只要能在足球場或板球場上相遇就會沒有興趣在戰場上相遇的話，我都倍感詫異。

98. It is impossible to say simply for the fun and exercise: as soon as the question of prestige arises, as soon as you feel that you and some larger unit will be disgraced if you lose, the most savage combative instincts are around.

98.沒有可能僅僅為了娛樂或鍛煉而運動：一旦有了問題，一旦你覺得你輸了你和你所屬團體會有失體面時，你最野蠻的好斗本能就會被激發出來。

99. It has been found that certain bats emit squeaks and by receiving the echoes, they can locate and steer clear of obstacles------or locate flying insects on which they feed. This echo-location in bats is often compared with radar, the principle of which is similar.

99.人們已經發現，某些蝙蝠發出尖叫聲并靠接受回響來鎖定和避免障礙物——或者找到它們賴以為生的昆蟲。蝙蝠這種回響定位法常拿來和原理與之很相近似的雷達相比。

100. As the time and cost of making a clip drop to a few days and a few hundred dollars, engineers may soon be free to let their imaginations soar without being penalized by expensive failure.

100.隨著芯片制造時間和費用降低到了幾天和幾百美元，工程師們可能很快可以任他們的想象馳騁而不會被昂貴的失敗所懲罰。