标题: 陈向东逻辑 [打印本页] 作者: jeans2011 时间: 2012-7-23 10:44 标题: 陈向东逻辑 30. A recent survey of all auto accident victims in Dole Country found that, of the severely injured drivers and front-seat passengers, 80 percent were not wearing seat belts at the time of their accidents. This indicates that, by wearing seat belts, drivers and front-seat passengers can greatly reduce their risk of being severely injured if they are in an auto accident. The conclusion above is not properly drawn unless which of the following is true? A. Of all the drivers and front-seat passengers in the survey, more than 20 percent were wearing seat belts at the time of their accidents. 答案是A，我就想知道有A怎么能推出题中的结论的？