费费逻辑完全摸不着头绪，急！

jjll

以下是引用apple711在2005-12-1 18:53:00的发言：

我的逻辑实在是太菜了，做费费一个小test１８道要错８个，郁闷的要死！１２月初就要考了，请大家帮帮忙，看看我的思路到底是哪里出问题了．．．谢谢！先看一个吧

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.

这个题目答案是选c没有问题，可是我怎么觉得a,b都没有办法排除呢？我错选了第２个，因为觉得也是个削弱啊．因为如果 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，那么就直接说明了，就业招聘的人员组成不是退学的，所以就削弱了．．．

要不开篇的那个关于army的例子有什么作用呢？？？

题目的结论是the republic’s recruitment rates for 18-year-olds depend substantially on recruitment rates for high school dropouts. 即国家18岁的招生比率主要依赖于招辍学人的比率。

前提是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. 即1980到1986年间18岁招生比率和辍学的比率同样升高。

C反驳说1980到1986年间18岁毕业生的比率也同样的升高了，也就说并不只依赖于辍学生的比率升高。

题目的关键是招生的比率究竟依赖于哪类学生的比率的问题。

A说的绝对数值，所以不对。B就更不相关了。

jjll

23题是A吗？

jjll

23题的结论是some of the nine cancellations were probably due to something else，也就是说认为不是因为mechanical problems，原因是it is unlikely that Swift would have the mechanical problems with more than one or two scheduled flights on a single day。

A说的是担任the nine canceled flights任务的不仅仅是one or two scheduled flights。你把它取非，也就是说如果这9个被取消的飞行都是这一两架飞机担任的话，那就仍然很有可能是机械原因了。