这道题的答案是D，我选得B。 我的想法是，文章中说了 有了TURNPIKES交通的成本下降了，所以我想的是B选项中说的利润更高就对了。 实在想不明白为什么不想B？
Transportation was becoming less of a problem for those who wished to move west and for those who hand farm surpluses to send to market. Prior to 1815, western farmers who did not live on navigable waterways were connected to them only by dirt roads and mountain trails. Livestock could be driven across the mountains, but the cost of transporting bulky grains in this fashion was several times greater than their value in eastern markets. The first step toward an improvement of western transportation was the construction of turnpikes. These roads made possible a reduction in transportation costs and thus stimulated the commercialization of agriculture along their routes.
8.Paragraph 4 suggests that turnpikes affected farmers by
A making the price of grain uniform for both eastern and western farmers
B making western farm products more profitable than eastern farm products
C allowing farmers to drive their livestock across mountain trails
D allowing a greater number of farmers to sell their farm products in a commercial market
B选项是虚假比较。成本下降了，确实可以说利润提高了，但不能得出A的利润就一定比B高。从这个角度说，B选项也有过度推断的感觉。
哦对哈，这点我看掉了。确实是。那为什么要选D呢？ 原文中也没有提到a greater number of farmers sell their farm products啊。我当时就觉得D选项直接就排除了。