订购手续费、催货跟踪费、收货费、人员工资等都属于（）成本。
参考答案：订购
下列食物中主要为人体提供蛋白质的是
A．牛油
B．蔬菜
C．米饭
D．牛奶
This was but an additional testimony of the superiority of the socialist economic system over the capitalist economic system.
A．proof
B．witness
C．evidence
D．validity
