题目

Much to his surprise，he invited only twenty friends to the dinner，but       came．    A．twice as many as                   B．as many as twice    C．twice as many                       D．twice more than 答案：C某产品的广告费用x与销售额y的统计数据如下表广告费用x（万元）4235销售额y（万元）49263954  根据上表可得回归方程中的为9.4，据此模型预报广告费用为6万元时销售额为（ ）A．63.6万元B．65.5万元C．67.7万元D．72.0万元