下列不属于变动成本的费用是( )。
A．原材料消耗
B．生产人员工资
C．包装费
D．折旧费
参考答案：D
Mr. Zhang gaVeall textbooks to all the pupils, except___________ who had already taken tem.
A．these
B．dnes
C．the ones
D．the others
GWl6．17型隔离开关动触片与静触杆有（）个接触点
A.2
B.4
C.6
D.8
