They were made by the lovely girl.[ ]
A. to laugh
B. laugh
C. laughing
D. laughed
答案:A
并不是每次出现良好行为都给予强化,这称为( )。
A.不定时强化
B.间歇强化
C.连续强化
D.完全强化
返矿有利于烧结生产,越多越好。