The east-west rail lines stimulated the settlement and agricultural development of the Midwest. By 1860 Illinois, Indiana, and Wisconsin had replaced Ohio, Pennsylvania, and New York as the leading wheat-growing states. Enabling farmers to speed their products to the East, railroads increased the value of farmland and promoted additional settlemen. in turn, population growth in agricultural areas triggered industrial development in cities such as Chicago, Davenport (Iowa), and Minneapolis, for the new settlers needed lumber for fences and houses and mills to grind wheat into flour.
According to paragraph 2, one effect of the increased agricultural development in the Midwest was to
B. increase the demand for industrial products from Midwestern cities
C. encourage the extension of east-west rail lines to the Midwest
D. reduce the pressure on Midwestern farmers to get their products to market faster
答案是B。 demand如何看出来?如果说rail way→mideast settlement +agricultural development
→ (wheat grow↑, speed products to east)→industrialization,D也是说得通的,因为铁路是industrialization的一部分啊。。。。