第一题,the vast majority of those who test positive will be people who have used cocaine。被测出POSITIVE的人越多的肯定是那组使用了可卡因的人。上面之说了5%跟99%。没说到底有多少人在一组。缺少比较的基数。基本看到比例就用基数反驳。答案是C
第二题,Responsible psychologists always accept the possibility that new evidence will show that their theories are incorrect.用了一个a general principle