制造费用差异按其形成原因可分为价格差异和数量差异。
参考答案：错
---What are you doing on your next day _____________?
---I want to have a good rest at home because I’m very tired these days.
A．off
B．on
C．of
D．up
在发文字号中，代号应该放在( )
A．最前边
B．中间
C．最后边
D．随意放置
