为了保持电子汽车衡的计量准确,应定期对其进行().
参考答案:周期检定
I have to go now. Please remember to __ the lights when you leave.[ ]
A. turn off
B. turn down
C. tum up
D. tum on
联结的增强和削弱取决于学习者的心理调节和心理准备。