请大家帮我看下这一题，谢谢

AnttiZhang

19. In Kravonia, the average salary for jobs requiring a college degree has always been higher than the average salary for jobs that do not require a degree.  Current enrollments in Kravonia’s colleges indicate that over the next four years the percentage of the Kravonian workforce with college degrees will increase dramatically.  Therefore, the average salary for all workers in Kravonia is likely to increase over the next four years.

Which of the following is an assumption on which the argument depends?

A.    Kravonians with more than one college degree earn more, on average, than do Kravonians with only one college degree.
B.    The percentage of Kravonians who attend college in order to earn higher salaries is higher now than it was several years ago.
C.    The higher average salary for jobs requiring a college degree is not due largely to a scarcity among the Kravonian workforce of people with a college degree.
D.    The average salary in Kravonia for jobs that do not require a college degree will not increase over the next four years.
E.    Few members of the Kravonian workforce earned their degrees in other countries.
  Answer: C
虽然我排除了一些选项，但是我不明白C的逻辑，请问谁能帮我解释下C的思路，为什么选C？像C说的，如果市场上不缺有degree的人，那么就算四年内有degree的人增加了，平均工资也不一定会升啊。那C怎么会是假设呢

billsq

谈谈个人的理解啊，C的核心就在一个scarcity，即workforce with a college degree的稀少不足，也就是说他们这群人的高工资不是由于大学生劳动力的稀少不足，（推论，而在于大学生劳动力的真实能力），因此next four year尽管大学生劳动力的比例会大幅上升，不会影响其含金量。这就是所需的假设。
如果高工资源于大学生劳动力的稀少性，那么今年（比如）有10个大学生，大家的工资是5000一个月，明年，有1000个大学生，稀少性没有了，大家的工资是50一个月，那么实际上，average salary 是没有变化的。

sealg

==》逻辑框架背景：1. 有大学学历的人的平均工资》没有大学学历的人的平均工资 2. 未来的4年终，有学历背景的人数会增加
结论：所有人的平均工资在未来四年中都会增加

A.    Kravonians with more than one college degree earn more, on average, than do Kravonians with only one college degree.==》原文不是讨论有几个degree的问题，而是平均工资的问题，所以无关
B.    The percentage of Kravonians who attend college in order to earn higher salaries is higher now than it was several years ago.==》原文讨论的是未来4年的情况。不是拿现在和过去的情况作比较，所以无关
C.    The higher average salary for jobs requiring a college degree is not due largely to a scarcity among the Kravonian workforce of people with a college degree.==》用NOT DUE TO 排除了一种情况；就是工资的高不是因为学历的稀缺，所以是support conclusion的，即赞成未来大学人数多了，大家工资也会增多，最终导致平均工资增多。我们negate下来验证：The higher average salary for jobs requiring a college degree is due largely to a scarcity among the Kravonian workforce of people with a college degree.则说明，学历高工资高的原因是因为scarcity，所以以后人数增多的情况，将不会有高的大学学历的平均工资，则all workers的平均工资也就搞不起来了。所以是weaken conclusion，所以可以算是assumption
D.    The average salary in Kravonia for jobs that do not require a college degree will not increase over the next four years. ==> 没有大学学历的人的平均工资不增加的，后果就是2个可能性，就是维持不变，或者降低。对all workers 的平均工资未来的增加是没有帮助作用的。所以这个可以算是个非常弱得weaken，甚至not affect conclusion，因为起决定因素的是高学历人的平均工资，而不是没有学历人的工资
E.    Few members of the Kravonian workforce earned their degrees in other countries.说的是other countries的情况，和本题无关

AnttiZhang

请问像这样的思维过程，在考场上，能很快完成么？

cptbtptp

我很白的选了D。试着理解C，感觉是排除它因的支持。除非也可以得到，D是有点不相关