完型填空練習

Many theories concerning the causes of juvenile delinquency (crimes committed by young people) focus either on the individual or on society as the major contributing influence. Theories (21) ____ on the individual suggest that children engage in criminal behavior (22) ____ they were not sufficiently penalized for previous misdeeds or that they have learned criminal behavior through (23) ____ with others. Theories focusing on the role of society that children commit crimes in (24) ____ to their failure to rise above their socioeconomic status (25) ____ as a rejection of middle-class values.
Most theories of juvenile delinquency have focused on children from disadvantaged families, (26) ____ the fact that children from wealthy homes also commit crimes. The latter may commit crimes (27) ____ lack of adequate parental control. All theories, however, are tentative and are (28) ____ to criticism.
Changes in the social structure may indirectly (29) ____ juvenile crime rates. For example, changes in the economy that (30) ____ to fewer job opportunities for youth and rising unemployment (31) ____ make gainful employment increasingly difficult to obtain. The resulting discontent may in (32) ____ lead more youths into criminal behavior.
Families have also (33) ____ changes these years. More families consist of one parent households or two working parents; (34) ____, children are likely to have less supervision at home (35) ____ was common in the traditional family (36) ____. This lack of parental supervision is thought to be an influence on juvenile crime rates. Other (37) ____ causes of offensive acts include frustration or failure in school, the increased (38) ____ of drugs and alcohol, and the growing (39) ____ of child abuse and child neglect. All these conditions tend to increase the probability of a child committing a criminal act, (40) ____ a direct causal relationship has not yet been established.
21.[A] acting [B] relying [C] centering [D] cementing