【正确答案】 B

【答案解析】[听力原文] One of the most popular myths about the United States in the nineteenth century was that of the free and simple life of the farmer. It was said that farmers worked hard on their own land to produce whatever their families needed. They might sometimes trade with neighbors; but in general they could get along just fine by relying on themselves, not on commercial ties with others. This is how Thomas Jefferson idealized the farmer at the beginning of the nineteenth century, and, at that time, this may have been close to the truth—especially on the frontier. But by mid-century, sweeping changes in agriculture were well under way—as farmers began to specialize in the raising of crops such as cotton or corn or wheat. By late in the century, revolutionary advances in farm machinery had vastly increased production of specialized crops. And the extensive network of railroads had linked farmers throughout the country to markets in the East and even overseas. By raising and selling specialized crops, farmers could afford more and finer goods and achieve a much higher standard of living—but at a price. Now, farmers were no longer dependent just on the weather and their own efforts. Their lives were increasingly controlled by banks, which had power to grant or deny loans for new machinery, and by the railroads, which set the rates for shipping their crops to market. As businessmen, farmers now had to worry about national economic depressions and the influence of world supply and demand on, for example, the price of wheat in Kansas. And so, by the end of the nineteenth century, the era of Jefferson's independent farmer had come to a close. What's the main feature of American farmers' life in the 19th century? 短文开篇提到19世纪的美国最流行的故事之一就是关于农民自由简单生活的故事，然后解释道农民在他们自己的土地上辛勤工作，生产他们家庭所需的产品，他们有时可能会与邻居进行交易，但通常都能靠自己过活，不用与他人交易，所以19世纪美国农民的主要特征就是过着自给自足的生活，故选B。