[简答题]

People in the United States in the nineteenth century were haunted by the prospect that unprecedented change in the nation’s economy would bring social chaos. (46) In the years following 1820, after several decades of relative stability, the economy entered a period of sustained and extremely rapid growth that continued to the end of the nineteenth century. (47)Accompanying that growth was a structural change that featured increasing economic diversification and a gradual shift in the nation’s labor force from agriculture to manufacturing and other nonagricultural pursuits.
Although the birth rate continued to decline from its high level of the eighteenth and early nineteenth century, the population roughly doubled every generation during the rest of the nineteenth centuries. (48)As the population grew, its makeup also changed. Massive waves of immigration brought new ethnic groups into the country. Geographic and social mobility downward as w

最新试题

• ●    抗热性
• ●    [单选题]在型号为150YⅠ-67×6'的离心泵中,'6'表示( ).
• ●    In the latter case the {{U}}outcome{{/U}} can be s
• ●    [判断题]现场倒闸操作应执行唱票、复诵制度，宜全过程录音。
• ●    [单选题]焊接冷裂纹产生的主要原因是( )。
• ●    [不定项选择题]传统轮轨交通轨道是由钢轨、轨枕、（ ）等组成。