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。

　　76. The scourge of HIV/AIDS currently engulfing the world will quite likely be brought under control within the next few years thanks to the untiring efforts of scientists and researchers worldwide .

　　现在席卷世界的艾滋病的祸害很有可能由于全世界科学家和研究人员的不懈努力在未来几年内得到控制。

　　77. The incidence rate of cancer mainly stems from several factors , including inappropriate diets , poor healthcare practices and the lack of early detection . Continuing medical advances and rising awareness do , however , offer promising hope for the future .

　　癌症的发病率主要由以下诸多因素引起，包括不适当的饮食、不好的保健习惯以及没有及早发现。然而，医学的不断进步和对此不断增强的关注给未来带来了很大的希望。

　　78. Increased urban pollution levels and the mounting death toll from motor vehicles accidents can mainly be attributed to the glut of automobiles appearing on city roads in recent years . Detrimental factors will quite likely outweigh the benefits of rising automobile usage .