问题 选择题

下列图示实验操作中,正确的是

A.稀释浓硫酸

B.读取液体体积

C.滴加液体

D.CO2的验满

答案

 

题目分析:A选项稀释浓硫酸要酸入水;B选项读取液体的体积,实现与量筒中的液体最低处保持水平是正确的叙述;C选项滴加液体要悬空垂直滴加;D选项二氧化碳的验满,燃着的木条放到集气瓶口,故答案选择B 

单项选择题

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 (51) on the individual suggest that children engage in criminal behavior (52) they were not sufficiently penalized for previous misdeeds or that they have learned criminal behavior through (53) with others. Theories focusing on the role of society suggest that children commit crimes in response to their failure to rise above their socioeconomic status, (54) as a rejection of middle-class values. Most theories of juvenile delinquency have focused on children from disadvantaged families, ignoring the fact that children from wealthy homes also commit crimes. The latter may commit crimes (55) lack of adequate parental control. All theories, however, are tentative and are (56) to criticism. Changes in the social structure may indirectly (57) juvenile crime rates. For example, changes in the economy that lead to fewer job opportunities for youth and rising unemployment (58) make gainful employment increasingly difficult to obtain. The resulting discontent may in turn lead more youths into criminal behavior. Families have also (59) changes these years. More families consist of one-parent households or two working parents; consequently, children are likely to have less supervision at home (60) was common in the traditional family structure. This lack of parental supervision is thought to be an influence on juvenile crime rates.

59().

A.survived 

B.noticed 

C.undertaken 

D.experienced

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