单项选择题
A．plastic drum；gunny bag；wooden case B．wooden ease；plastic drum；gunny bag C．wooden case；gunny bag；plastic drum D．plastic drum；wooden case；gunny bag
A．business；invoice；contract B．foreign trade；contract；invoice C．business；L/C；contract D．foreign trade；invoice；contract
A．5 B．8 C．10 D．15