实物货币本身又分为（）与（）两种。
参考答案：非金属实物货币；金属实物货币
After many years’ hard working, his parents managed to ________ the debts for his education at university.
A．pay for
B．pay back
C．pay off
D．pay out
当发生重要事件或紧急事件必须迅速处理时，采取什么策略处理冲突？
