—I didn’t go to work yesterday because my car broke down.

—You _______ mine.I wasn’t using it then.

A．might borrow

B．could have borrowed　

C．must have borrowed

D．ought to borrow

与运输成本存在二律背反关系的是( )。

A．保管费用

B．订货费用

C．存货持有成本

D．运输费用