The changing conditions of American life, marked by the spreading mill towns of New England, New York, and Pennsylvania and the growth of cities like Buffalo, Cincinnati, Louisville, St.
——美国生活条件的变化,以新英格兰、纽约和宾夕法尼亚的工厂城镇的扩张以及布法罗、辛辛那提、路易斯维、圣路易斯等城市的发展为标志。