一做就错,哪位帮忙解释一下

xuelin

An annually conducted, nationwide survey shows a continuing marked decline in the use of illegal drugs by high school seniors over the last three years.
Which of the following, if true, would provide most support for concluding from the survey results described above that the use of illegal drugs by people below the age of 20 is declining?
(A) Changes in the level of drug use by high school seniors are seldom matched by changes in the level of drug use by other people below the age of 20.
(B) In the past, high school seniors were consistently the population group most likely to use illegal drugs and most likely to use them heavily.
(C) The percentage of high school seniors who use illegal drugs is consistently very similar to the percentage of all people below the age of 20 who use illegal drugs.
(D) The decline revealed by the surveys is the result of drug education programs specifically targeted at those below the age of 20.D
(E) The number of those surveyed who admit to having sold illegal drugs has declined even faster than has the number who have used drugs.
c和d怎么判断阿,我选的d,也说得通阿

yingliuhe

D是说The decline。。。is the result of跟问题无关啊。
不管是什么原因引起的decline，要说明20岁以下也下降了，除非20岁以下的比例跟高中生比例很相似，即C，才可以得出结论。

Julianna

d答案有一个flaw, 就是它已经假设了high school senior的比例就是people below the age of 20的比例, 事实上这二者并不是一样的,二十岁以下的人并不全都是高中生.
要使题目中的理由a decline in the use of illegal drugs by high school seniors推断出结论the use of illegal drugs by people below the age of 20 is declining, 必须有一个前提存在,那就是C答案, 即high school senior的比例和people below the age of 20的比例是相似的
这道题我刚做的时候也中招了,没细看,呵呵
btw: 楼主是不是在巴黎呀?什么时候考?

amo

加强题，C是在前提和结论中架设桥梁，所以是对的，其余选项都涉及到文中没有出现的概念可以用排除法排除，鄙人拙见

xuelin

GET IT! THANKS EVERY GGJJ!

以下是引用Julianna在2004-2-3 0:44:00的发言：
btw: 楼主是不是在巴黎呀?什么时候考?

YES, JULIANNA,JUST WITHIN TWO WEEKS.YOU ARE IN PARIS TOO?

Julianna

我也在巴黎考,2月18号
基本上刚开始准备, hoho, 一直在跟取消考试的念头做斗争
你几号考?

terry_awesome

………………巴黎……浪漫之都啊。
架桥梁是什么意思？