单选题 Sales went up in the stores during December, but ______ again after Christmas.
【正确答案】 A
【答案解析】[分析] 习语辨析 A．dropped off离开，散去，逐渐减少，死去；B．dropped out不参与，离去，放弃；D．dropped on训斥，惩罚；此句意为：各商店的销售额在十二月份上升，但圣诞节后又下降了。所以答案为A。