OG-46请教为什么选A？谢谢

46. Kale has more nutritional value than spinach. But since collard greens have more

nutritional value than lettuce, if follows that kale has more nutritional value than lettuce.

Any of the following, if introduced into the argument as an additional premise, makes the

argument above logically correct EXCEPT:

A. Collard greens have more nutritional value than kale

B. Spinach has more nutritional value than lettuce

C. Spinach has more nutritional value than collard greens

D. Spinach and collard greens have the same nutritional value

E. Kale and collard greens have the same nutritional value

假设题（桥梁型）

已知K>S; C>L

问下列选项除了哪个都能使不等式K>L成立

A选项C>K不能保证目标不等式成立，举例如C=5 K=2 L=4

Thanks for your prompt response goldenbean! I cannt undanstand "but since" and "it follows that" at first.

再请教， 是不是题目里写错了！！？？？？

But since collard greens have more

nutritional value than lettuce, if follows that kale has more nutritional value than lettuce. if 应该是it， 对不？ 否则，这个逻辑好像不是那样的？？？帮忙回答以下，谢谢！！！

if follows that kale has more nutritional value than lettuce是结论,也就是后面说的argument,选项是需要增加的论据.

个人理解是省略了it,但是如果IF没有了，就不知道argument是什么了

以下是引用goldenbean在2005-3-14 9:09:00的发言：

假设题（桥梁型）

已知K>S; C>L

问下列选项除了哪个都能使不等式K>L成立

A选项C>K不能保证目标不等式成立，举例如C=5 K=2 L=4

同意，C>L=>K>L,需要额外条件K>C。A给出一个相反的条件，自然不能得出文中的推导结论。

这里估计主要是对But since .....,if follows....的理解问题，同意if是it的印刷错误，意思是“因为....，那么就有.....”。