“杀一儆百” 所产生的强化作用主要属于[ ]
A．直接强化
B．替代性强化
C．自我强化
D．正强化
参考答案：B
临床上对乳牙近髓深龋的治疗最好采用
A．直接盖髓
B．间接盖髓
C．冠髓切除
D．干髓术
E．根管治疗
The teacher spoke so fast that it was hard for the students to ______ what he was saying.
A．take in
B．take off
C．take on
D．take after
