94. When 100 people who have not used cocaine are tested for cocaine use, on average only 5 will test positive. By contrast, of every 100 people who have used cocaine 99 will test positive. Thus, when a randomly chosen group of people is tested for cocaine use, the vast people is tested for cocaine use, the vast majority of those who test positive will be people who have used cocaine. A reasoning error in the argument is that the argument (A) attempts to infer a value judgement from purely factual premises (B) attributes to every member of the population the properties of the average member of the population (C) fails to take into account what proportion of the population have used cocaine (D) ignores the fact that some cocaine users do not test positive (E) advocates testing people for cocaine use when there is no reason to suspect that they have used cocaine
此题看不明白,请NR解释. Thus, when a randomly chosen group of people is tested for cocaine use, the vast people is tested for cocaine use, the vast majority of those who test positive will be people who have used cocaine. 上面两个句子是什么关系啊,怎么一个when引导的从句后有两个主句啊?本题意思也看不明白,请指点,谢谢! | 
