1.As more and more railroads and later interstate highways for trucks and cars and airports for planes were built, the crucial importance of the Mississippi and its various riverways diminished.
随着越来越多的铁路以及后来为卡车和汽车
造的州际高速公路,还有为飞机
造的机场,密西西
河及其各种河流的重要性都减弱了。