[求助]请教几个问题

2\
X-ray examination of a recently discovered painting ---- judged by some authorities to be a self-protrait by Vincent van Gogh ---- revealed an underimage of a woman’s face. Either van Gogh or another painter covered the first painting with the portrait now seen on the surface of the canvas. Because the face of the woman in the underimage also appears on canvases van Gogh is known to have painted, the surface painting must be an authentic self-protrait by van Gogh.
The conclusion above is properly drawn if which of the following is assumed?
many painted canvases that can be reliably attributed to van Gogh contain underimages of subjects that appear on at least one other canvas that van Gogh is known to have painted.
[C] Any painted canvas incorrectly attributed to van Gogh would not contain an underimage of a subject that appears in authentic paintings by that artist.

Answer is C  这题的题目看得就不太懂。我错选了B。C的意思是从题目（有底影——〉真品）推出（赝品——〉没有底影）吗？B的意思是不是说真品有底影现象有很多先例作为前提可以吗？

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No computer will ever be able to do everything that some human minds can do, for there are some problems that cannot be solved by following any set of mechanically applicable rules. Yet computers can only solve problems by following some set of mechanically applicable rules.

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

At least one problem not solvable by following any set of mechanically applicable rules is solvable by at least one human mind.

[E] Every problem that is solvable by following at least one set of mechanically applicable rules is solvable by at least one human mind.

Answer is B 这道题好绕。。我错选的E。不知道E哪里错了阿？

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Medical research findings are customarily not made public prior to their publication in a medical journal that has had them reviewed by a panel of experts in a process called peer review. It is claimed that this practice delays public access to potentially beneficial information that, in extreme instances, could save lives. Yet prepublication peer review is the only way to prevent erroneous and therefore potentially harmful information from reaching a public that is ill equipped to evaluate medical claims on its own. Therefore, waiting until a medical journal has published the research findings that have passed peer review is the price that must be paid to protect the public from making decisions based on possibly substandard research.

The argument assumes that

[A] unless medical research findings are brought to peer review by a medical journal, peer review will not occur.

[D] all medical research findings are subjected to prepublication peer review.

Answer is A  这道题也是看不大懂。。觉得题目没有包含评阅不发生的情况阿？

请高人指教。。感激ing！

我来说说第一题。原文一开始说的是一幅画底下的可以确定是梵高画的，推导出面上的也是梵高的真迹自画像。这里缺的一层意思就是由底下的推出面上的过程。看到C选项， Any painted canvas incorrectly attributed to van Gogh would not contain an underimage of a subject that appears in authentic paintings by that artist.意思是所有不是梵高真迹画都不会在底下有他的真迹。与它相等的逆否命题是All painted canvas that contain an underimage of a subject that appears in authentic paintings by the artist would be attributed to van Gogh.就是说在底下有梵高真迹的画表面上也是梵高的真迹。这个就是从底下的推导上面的一层意思。所以选C。