The invention of the method of altering childrens behavior. is owing to______. A．the desirable behavior B．reinforced practice C．decades of study D．replacement of unwanted behaviors
A. A．the B.reinforced C.decades D.replacement
【参考答案】
C 属因果细节题。将题目内容与文章第一句的内容进行对等替换即可得出结论，文章提到通过50多年的研究，人们才得以了......