求救，狒狒 20题，谢谢！

beryl8

20. A rise in the percentage of all 18-year-olds who were recruited by the armed services of a small republic between 1980 and 1986 correlates with a rise in the percentage of young people who dropped out of high school in that republic. Since 18-year-olds in the republic are generally either high school graduates or high school dropouts, the correlation leads to the conclusion that the republic’s recruitment rates for 18-year-olds depend substantially on recruitment rates for high school dropouts.

Which one of the following statements, if true, most weakens the argument?

(A) A large number of 18-year-old high school graduates were recruited for the republic’s armed services in 1986 than in 1980. ?
(B) Many of the high-technology systems used by the republic’s armed services can be operated only by individuals who have completed a high school education.
(C) Between 1980 and 1986 the percentage of high school graduates among 18-year-olds recruited in the republic rose sharply.
(D) Personnel of the republic’s armed services are strongly encouraged to finish their high school education.
(E) The proportion of recruits who had completed at least two years of college education was greater in 1986 than in 1980.


答案C, 不明白为什么D不对呢，求指教，谢谢大家

Maimai.

premise:  Since 18-year-olds in the republic are generally either high school graduates or high school dropouts （18岁的小孩要么在读高中，要么辍学）
conclusion： 18岁参军的人数增加了，而因为正在上高中的人无法参军，所以参军的人数取决于辍学的人数

weaken 了premise：Between 1980 and 1986 ，18岁就高中毕业并且参军的比例增加了很多。就是给出了第三种情况：18岁已经高中毕业了。

d 说的是参军之后的情况，无关。

DreamTurelater

呵呵解释

eshopaholic

fact one: 十八岁参军的人的比例提高了  fact two: 高中生（18岁）失学率提高了

fact one correlates with fact two, leading to a conclusion: fact two 导致 fact one

求削弱，找出导致fact one 的其他理由，如C