选译自:(美国)2007年的《总统经济报告》第7章(Chapter Seven of Economic Report of the U.s.President,Transmitted to the Congress,February2007)引言在现代经济中,企业不仅仅从本地或全国市场购买和销售产品,而且企业的供应商通常来自全国各地。为了在世界范围内采购并销售其自己的商品,通常需要将一种货币兑换成另一种货币。例如,当英国的公司和美国的公司进行贸易的时候,美国公司可能会用美元支付,然而英国公司却需要用英镑支付其生产的成本。当美国公司支付英国公司后,下面的事件之 In the modern economy, companies not only from the local or national markets, but also from the United States, Buy and sell products, and companies often come from suppliers all over the country. In order to procure and sell its own products worldwide, it is often necessary to convert one currency into another. For example, when a British company trades with a U.S. company, U.S. companies may pay in U.S. dollars. British companies, however, need to pay for their production in sterling. When a U.S. company pays a British company, the following event