Exports and imports of goods between nations with different units of money introduce a new economic factor: the rate of foreign exchange at which the currency of one country exchanges for the currency of another.

• 使用不同货币的国家之间要进出口货物，就必须引人一个新的经济因素：把一个国家的货币换成另一个国家货币的外汇兑换率。