gwd2--17，不同观点答案，欢迎讨论

Q17:

The quality of unrefined olive oil is not actually defined in terms of acidity, yet extensive tests have shown that the less free oleic acid an unrefined olive oil contains per liter, the higher its quality.  The proportion of free oleic acid that an olive oil contains is an accurate measure of the oil’s acidity.

If the statements above are all true, which of the following conclusions is best supported by them?

A.      When an olive oil is refined, the concentration of oleic acid in the oil is reduced.

B.      The quality of an unrefined olive oil can be determined only by accurately measuring its acidity.

C.      If an unrefined olive oil is intermediate in acidity between two other unrefined olive oils, it will also be intermediate between them in quality.

D.      Free oleic acid is the only acid that unrefined olive oil contains.

E.      People who judge the quality of unrefined olive oils actually judge those oils by their acidity, which the judges can taste.

   Answer: c

我认为选B. 题目：unrefined olive oil的质量如何其实不是由酸度acidity这个概念来界定的，但是大量实验发现某种酸（free oleic acid）越少（注释：与后面的proportion对应）,unrefined olive oil质量越高。某种酸在油中的proportion(注释：比例与前面的the less….contain per liter对应)是acidity酸度的一个accurate measure精确测量方法。

即：acidity只是简单反映整体酸度问题，所以不可以actually defined. 但是通过测量各种酸中free oleic acid 的比例，就可以反映质量情况。而测量free oleic acid的比例正是测量酸度的一个精确方法（隐含：不是简单看酸度整体量而是看比例的指标）

题目中的逻辑关系很明确

acidity不可以直接推出quality. 但因为free oleic acid--à quality,   且free oleic acid---àacidity,

所以acidity--àquality 但必须保证free oleic acid发挥中间作用，即accurate measure of acidity.(两者等价)

因此很明显答案是B

出现的关键词是Only, accurately measuring.

C选项不对。拥有酸度量为中间值（intermediate in acidity）的某种酸其各种酸度中的free oleic acid的比例无从知道，所以当然无法判断其质量处于什么位置。

A.       E选项是无关项。D选项显然不对，如果Free oleic acid是唯一的酸的话，acidity的量就完全由这种酸决定了，那么文章第一句话就不合理了。所以其实这个选项也提示我们油中含有多种酸。

感觉这道题的关键是考察混淆两个概念，酸度量acidity和比例问题。

大家感觉如何呢？

以上是我的个人看法，我才开始复习，7天后上考场，所以以前大家对此题的讨论情况不大了解。不过我看了以下的帖子，发现大家的答案跟我不一样所以贴上来看看，欢迎发表意见。

原来的讨论情况如下http://forum.chasedream.com/dispbbs.asp?BoardID=24&ID=58172

（另外，我刚做了gwd1，2套，发现很多主要是逻辑题答案我不认同的，请问那些答案都得到确认了么？）

I think the answer should be C.

In the statement it says "The proportion of free oleic acid that an olive oil contains is an accurate measure of the oil’s acidity", so acidity is the measurement of quality.

B is incorrect because it says "The quality of an unrefined olive oil can be determined only by accurately measuring its acidity."  And in the statement it doesn't say "only". I can also accurately measure the amount(or concentration) of free oleic acid(instead of the acidity) to determine the quality.

I don't know where you got the answer but I think almost all of them are correct, you should double check the questions if you have a different answer.

你没能说服我

某种油的质量不是由酸度来定的－测试发现某酸越少，该油质量越高－某酸是该油酸度精确的量度。

B不是答案。B说只能通过酸度精准的测量来得出该油质量。这个不一定的，完全有可能有其它方法也能测出该油质量，原文的信息推不出该结论。

C正确。酸度反映油质量。因此一般的酸度推出一般的质量。