现在，每个国家都与其他国家做买卖。如果一个国家生产的香蕉超过了需求，但不生产卡车，它就可能与另外一个不产香蕉，但有剩余卡车的国家进行交换。
The things a country sells to another country are called exports. The things a country buys from another country are called imports. International payments1 are made in the currency of the exporting country. Therefore, the paying countries have to buy the currency of the exporting country in the foreign exchange market.
一个国家将货物卖给另一个国家叫出口，一个国家从另一个国家购买货物叫进口。国际支付是用出口国货币进行的，所以，付款国必须到外汇市场上购买出口国的货币。
The exchange rate is the price of foreign currency in terms of domestic2 currency, and it varies3 from time to time. Sometimes a United States dollar is worth twelve pesos in Mexico. Another time it may be worth eight pesos.
外汇汇率是以本国货币表示的外国货币的价格。汇率会不时地波动，有时一美元值十二墨西哥比索，有时只值八比索。
Today international trade is big business. Hundreds of business houses and banks are engaged in work connected with international trade. Wholesale4 houses buy in large quantities from other countries. They sell in smaller quantities to shopkeepers and other merchants. In turn, these merchants and shopkeepers sell in still smaller amounts to individual buyers.
现在，国际贸易是大买卖，许多商行和银行从事与国际贸易有关的业务。批发商从其他国家大批量购买，再小批量卖给商家和其他商人，由他们再转手，零售给单个顾客
