only if 引导从句到底是条件还是结论？

183077142 · 发表于 2011-3-27 21:43:31

No mathematical proposition can be proven true by observation. It follows that it is impossible to know any mathematical proposition to be true.

The conclusion follows logically if which one of the following is assumed?

(A) Only propositions that can be proven true can be known to be true

(B) Observation alone cannot be used to prove the truth of any proposition

(C) If a proposition can be proven true by observation then it can be known to be true.

(D) Knowing a proposition to be true is impossible only if it cannot be proved true by observation

(E) Knowing a proposition to be true requires proving it true by observation

我在DE里面纠结选了D 因为我觉得D的意思是
D 知道定理为真，是不可能的，只要它不能被观察证实这里only if 引导的后面我认为是条件
逻辑关系是只要定理不能被证实，知道定理为真是不可能的

但是别人给出的解释是 D选项 IMPOSSIBLE KNOWN TO BE TRUE 推出 CANNOT BE PROVE BY OBSERVATION
请问大家only if 引导的是结论还是条件？

此题答案E

sdcar2010 · 发表于 2011-3-27 22:02:13

A only if B

A is the sufficient condition which leads to B.

B is the necessary condition for A to happen.

only if 引导从句到底是条件还是结论？

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only if 引导从句 到底是条件还是结论？

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only if 引导从句到底是条件还是结论？