GMAT逻辑中数量范围问题

数量的范围是逻辑题常考，特别是MUST BE问题，混淆答案也常来于此。下面一题是LSAT，先讨论，后再公布答案及解释。

The importance of the ozone layer to terrestrial animals is that it entirely filters out some wavelengths of light but lets others through. Holes in the ozone layer and the dangers associated with these holes are well documented. However, one danger that has not been given sufficient attention is that these holes could lead to severe eye damage for animals of many species.

Which one of the following is most strongly supported by the statements above, if they are true.

A). All wavelengths of sunlight that can cause eye damage are filtered out by the ozone layer where it is intact.

B). Few species of animals live on a part of the earth\'s surface that is not threatened by holes in the ozone layer

C). Some species of animals have eyes that will not suffer any damage when exposed to unfiltered sunlight

D). A single wavelength of sunlight can cause severe damage to the eyes of most species of animals

E). Some wavelengths of sunlight that cause eye damage are more likely to reach the earth\'s surface where there are holes in the ozone layer than where there are not,

分析部分：

The importance of the ozone layer to terrestrial animals is that it entirely filters out some wavelengths of light but lets others through. Holes in the ozone layer and the dangers associated with these holes are well documented. However, one danger that has not been given sufficient attention is that these holes could lead to severe eye damage for animals of many species.

Which one of the following is most strongly supported by the statements above, if they are true.

A). All wavelengths of sunlight that can cause eye damage are filtered out by the ozone layer where it is intact.错的原因：All wavelengths 太strong。原文只知完好的臭氧层滤掉一部分光，让一部分通过，并说通过的那部分对很多动物有害。从这点很容易误认有害的都给滤掉了。其实原文没说是否那通过的一部分是否含有有害波长。所以错。

原文问：is most strongly supported by the statements above，如果问哪个选项support 结论。A应该是个好选项。非常strong！但是因为是被原文支持，选项不能超越原文提供的范围：some wavelengths 不能推出all wavelengths，所以Ａ错了。

B). Few species of animals live on a part of the earth\'s surface that is not threatened by holes in the ozone layer错的原因：原文只说有HOLE可能会使很多动物受伤害，从这点也许可以推出有动物生活在受HOLE威胁的地方，但原文没说有没有动物生活在不受HOLE威胁的地方，故错。

C). Some species of animals have eyes that will not suffer any damage when exposed to unfiltered sunlight错的原因：有些人容易选这个，因为原文最后一句话说HOLE会伤害很多动物的眼睛，就是说很多动物的眼睛会受伤害，既然有很多的眼睛受伤害，就有不受伤害的。错。关键是理解原文最后一句话的many。其实相当于some ，表达的是有的概念，就是可以是1-100。相对或取非的概念为NONE。就是说它们可以包括全部100。所以有可能全部动物眼睛都会受HOLE伤害。即C可能对，也可能不对，不是MUST BE TRUE。故错。

我觉得这里不是ｓｏｍｅ的原因，而是全文说could lead to severe eye damage for animals of many species.，由于是答案被原文支持，所以答案一定不能超越原文的界限，因为原文为严重伤害很多种类的眼睛，我们只能得到　：有些种类的眼睛没有被严重的伤害　可以做绝对正确的推论，但是说有些种类的眼睛根本没有被伤害　就不能是ｍｕｓｔｂｅｒｉｇｈｔ的选项了。所以该选项不能成为正确选项。

D). A single wavelength of sunlight can cause severe damage to the eyes of most species of animals错的原因：也是容易选错，因为原文的最后一句话加上中文对MANY和 MOST（都是很多）的理解。其实MOST（多数）是指51-100。MANY指1-100。所以不能从MANY推出MOST，从MOST倒可以推出MANY。即原文用MOST，D选项用MANY，则为答案。

E). Some wavelengths of sunlight that cause eye damage are more likely to reach the earth\'s surface where there are holes in the ozone layer than where there are not,  从原文最后两句话可知完好的臭氧层滤掉了部分有害的光线，则说明有洞时，有害的光线更易到达地球。故对。

最后强调一点该问题虽然是MOST STRONGLY SUPPORTED，但不会出现两个能从原文MUST BE得出的答案，因为该题归为MUST BE TRUE题型，当然不存在支持的程度问题。