操作强化理论属于（）理论
A.社会行为
B.社会认知
C.社会学习
D.社会角色
参考答案：A
下列哪种药物对肾脏造成损害较少（）
A.青霉素
B.庆大霉素
C.卡那霉素
D.多粘菌素B
E.磺胺类药
Having questioned the spy for two days, the officer didn't ______ any valuable information. [ ]
A. associate
B. obtain
C. reform
D. cast
