export base theory

例句：

1. 1. The company is exporting its products to other countries.
   该公司正在将其产品出口到其他国家。
2. 2. The exports of the country's oil are increasing year by year.
   该国的石油出口量逐年增加。
3. 3. The export of goods has been a major source of income for the country.
   货物出口一直是该国的主要收入来源。