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.物理学和化学的一个成果是使得科学家们能在生物学和医学上获得重大发现。

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.根据默默无闻的小说制作优秀影片在美国由来已久，已经成为传统。

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.因为顾客认为最好的水果应该看起来也是最漂亮的，所以种植者必须提供能满足挑剔眼光的产品。

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.电视，这项从迅速变化和成长为标志的最普及和最有影响力的现代技术，正在步入一个新时代，一个极为成熟和多样化的时代，这将重塑我们的生活和世界。

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.他的教书生涯始于麻省理工学院，但是William Rainey Harper把他吸引到了新成立的芝加哥大学。他在那里正式任职长达整整一代人的时间。他的高级作文课上的学生觉得他在课上古板得可怕，但私下交流却富有同情和理解。

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