简述操作技能的培训要求。
参考答案：(1)准确地示范与讲解； (2)必要而适当的练习； (3)充分而有效的反馈； (4)建立稳定清晰的动觉。
The lazy boy _____there doing nothing all the afternoon, but he______ to his boss that he had finished what should be done.
A．lay; lied
B．lied; lying
C．laid; lay
D．lying; laid
营养强化
