Railroads changed the look of the United States. They cut through mountains, crossed through wide open prairies and joined together in cities. The railroads made transporting goods easier. They also gave many Americans the chance to move around the country._____________________For the train running down the track there is no right or wrong side. The track is simply the metal structure on which the train runs.铁路改变了美国的面貌.它们穿过群山,越过开阔的草原,把城市连接在一起.铁路使得货物运输更为容易,也给了很多美国人在全国各地迁徙的机会.________________________对铁轨上运行的列车来说,铁轨两边没有好坏之分.铁轨就是列车运行运行其上的金属结构.
