简述操作技能的训练要求。
参考答案：
（1）准确的示范与讲解。（2）必要而适当的练习。（3）充分而有效地反馈。
--___________? –I went to the mountains.
A．Where did you go on vacation?
B．What are you doing for vacation?
C．How did you go to the mountains?
D．How often do you go to the mountains?
双因素理论
