学校情境下学与教相互作用过程中的基本要素有（ ）。
A．学生
B．教师
C．教学内容
D．教学媒介
E．教学环境
参考答案：A,B,C,D,E
The boss____________ the worker how to do it, or the accident couldn't have happened.
A．can't have told
B．ought to tell
C．could have told
D．mustn't have told
桑葚按功效分类属于（）。
