第5题: [单项选择]It can be inferred from the passage that the mass production of steel caused ______. A. a decline in the railroad industry B. a revolution in the industrial world C. an increase in the price of steel D. a feeling of discontent among steel workers 参考答案:B 答案解析:文章最后指出“钢是工业时代的基本建筑材料”,据此可以推断,钢的大量生产将会带来一场工业革命,所以正确答案为B。