题目内容：
阅读下面文章，回答题。Many theories concerning the causes of juvenile delinquency ( crimes committed by young peo-ple) focus either on the individual or on society as the major contributing influence．Theories __16__ on the individual suggest that children engage in criminal behavior __17 __they were not sufficiently penalized for previous misdeeds or that they have learned criminal behavior through __18__ with others．Theories focusing on the role of society that children commit crimes in __19__ to their failure to rise above their socioeconomic status, or as a rejection of middle-class values．
Most theories of juvenile delinquency have focused on children disadvantaged families,__20__the fact that children from wealthy homes also commit crimes．The latter may commit crimes for lack of adequate parental control．All theories,however,are tentative and are __21 __to criticism．
Changes in the social structure may indirectly __22 __juvenile crime rates．For example, chan-ges in the economy that lead to fewer job opportunities for youth and rising unemployment __23 __make gainful employment increasingly difficult to obtain．The resulting discontent may in __24__ lead more youths into criminal behavior．
Families have also __25__ changes these years．More families consist of one-parent households or two working parents;__ 26__ , children are likely to have less supervision at home __27__ was common in the traditional family __28__ ．This lack of parental supervision is thought to be an influence on juvenile crime rates．Other identifiable causes of offensive acts include frustration or failure in school, the increased __29__ of drugs and alcohol, and the growing __30 __of child abuse and child neglect．All these conditions tend to increase the probability of a ehild committing a criminal act, although a direct causal relationship has not yet been established．
__________ A．acting
B．centering
C．relying
D．commenting
参考答案：
答案解析：