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 .

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 .

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 .

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 .

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 .

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 .

79. The rising divorce rate in China can , at least in part , be attributed to spousal incompatibility , disparities in education levels , changing social attitudes and the increasing upward mobility of the younger generation .

80. State-owned enterprises are not only failing because of inefficient management , but also because of their inability to awitch operational modes from the former planned economy to the new market economy .