语法与词汇 Here was the very heart of industrial America, the center of its most lucrative and characteristic activity.无
【正确答案】Lucrative means something that can produce a large profit. 
【答案解析】句意： 这里是工业美国的中心， 是其利润最丰厚和最有特色的活动中心。 lucrative指“获利多的， 赚钱的”。