为什么是否命题，不能得出结论啊？？

enou · 发表于 2011-9-9 16:08:48

74. Governments have onlyone response to public criticism of socially necessary services: regulation ofthe activity of providing those services. But governments inevitably make theactivity more expensive by regulating it, and that is particularly troublesomein these times of strained financial resources. However, since public criticismof childcare services has undermined all confidence in such services, and sincesuch services are socially necessary, the government is certain to respond.

Which one of thefollowing statements can be inferred from the passage?

A. The quality of child-care will improve.
B. The cost of providing child-care services will increase.
C. The government will use funding to foster advances in child-care.
D. If public criticism of policy is strongly voiced, the governmentis certain to respond.
E. If child-care services are not regulated, the cost of providingchildcare will not increase.

答案说E是否命题, 不能得到的结论？？
否命题，都不能得到结论吗？？
不懂诶……

cdwayne · 发表于 2011-9-9 17:05:23

From the 1st and the last sentences we know that the government is certain to respond to public criticism of socially necessary services--the child care service, which inevitably make more expensive, i.e., increasing the cost. (B)

(E) is incorrect, because IF child care services are regulated, the cost will increase, and (E) is a mistaken negation.

enou · 发表于 2011-9-9 19:26:19

恩~ 我对否命题这块不是特别了解……

想再请教下，
1、我怎么判断E是否命题呢？与原文相对应的话，原命题是什么啊？
2、E选项表示的否命题，是同时否定IF Q，（then） P，的Q和P嚒？

谢谢哈~~

cdwayne · 发表于 2011-9-10 00:10:06

given conditional relationship: A --> B

contrapositive: ~B --> ~A (must be true)
mistaken revision: B --> A (could be true; could be false)
mistaken negation: ~A --> ~B (could be true; could be false)

enou · 发表于 2011-9-10 02:05:41

有点头绪了……嘿嘿～　谢谢哈～

为什么是否命题，不能得出结论啊？？

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