71. Identifying the reasons for an emerging phenomenon which involves several complicated factors is far from an easy task . For example , some scientists attribute environmental deterioration to a series of natural factors , while others place the blame solely on inappropriate human behavior .

　　要找到涉及许多复杂因素的新现象的原因远非一件易事。例如，一些科学家把环境的恶化归结为一些自然因素，而另一些人把责任都推在人类不适当的行为上。

　　72. One doesn't have to look far to realize the direct correlation between smoking and cancer .

　　人们不用花费很大力气就能发现抽烟和癌症之间的直接联系。

　　73. The explanation for the phenomenon of the rising teenage suicide rate involves many complicated factors . Some attribute the rise to an overemphasis on early success , others point to mounting peer pressure , and still others to confusion over changing social values .

　　对上升的少年自杀率的解释涉及很多复杂的因素。有的人把上升的原因归结为过分强调少年时期的成功，有的人指出是因为不断增长的同伴之间的压力，还有人认为是对不断变化的社会价值的迷茫造成的。

　　74. The reasons for antisocial behavior are both complicated and varied . I suggest the phenomenon results from inappropriate role models and the lack of well-defined norms of behavior . However , the main reason is quite likely the continuing degeneration of social values .

　　反社会行为的原因既复杂又多样。我认为这种现象是不恰当的角色典型和缺少行为规范的很好的定义造成的。然而，主要原因很可能是不断贬低的社会价值。

　　75. The causes of racial hatred are not readily definable . Sociologists , however , attribute them to the misguided concept of a superior race and an innate mistrust of people of color . Perhaps the main cause is quite simply ignorance .

　　种族仇恨的起因没有现成的答案。然而，社会学家把原因归结为被误导的更高贵的种族的观念以及天生的对有色人种的不信任。主要原因可能仅仅是因为无知。

(责任编辑：田学江)