Now, the VOA Learning English program Words and Their Stories. Each week, we tell about American expressions and where they come from. Today we talk about railroads. Railroads were important to the development of the United States. ________________________现在是美国之音慢速英语词汇典故节目.每周我们都会讲述美国短语及其来源.今天我们讲述的是铁路.铁路对美国的发展曾经非常重要.________________________
