一道困扰了很久很久的逻辑题

bloomers

A recent survey of all auto accident victims in Dole Country found that, of the severely injuried 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.
B. Considerably more than 20 percent of drivers and front-seat passengers in Dole Country always wear seat belts when travelling by car.

C. More drivers and front-seat passengers in the survey than rear-seat passengers were very severely injured

D. More than half of the drivers and front-seat passengers in the survey were not wearing seat belts at the time of their accidents

E. Most of the auto accidents reported to police in Dole Country do not invole any serious injury.

painsper

A吗!

bloomers

是的， 是A，但是就是没有相通为什么

xiangxiangling

我试着解释一下，部队不要砸鸡蛋呀

   范围全面  一个整体中有80%人severely injuried and they didnt wear seatbell, another 20% were wearing seatbell at the time when the accidents happeded moreover, they were not severly injured…

elaineyll

题干中是争对the severely injuried drivers and front-seat passengers来进行推理的。

文中说有80%的the severely injuried drivers and front-seat passengers是没有系安全带，（那么有20%的重伤是系了安全带）由此得出要系安全带就会减少severely injure的结论。

A选项中是争对所有车祸来说的，即包括了severely injure在内的所有车祸。 在所有车祸中有多于20%的人是系了安全带，（就假设是30%的车祸是系了安全带），那么就可以说明系没系安全带在导致重伤车祸中确实是有关系的。重伤中系了安全带的人比例比车祸中系了安全带的人比例要少，那么系安全带在重伤中确实有好处。

所以，A选项加强了原文结论。

我大概是这么理解的。。。。估计也没说清楚。。。

bloomers

哦，是这么回事，我感觉有点明白了，谢谢大家的帮忙啊！