GRE阅读技巧之数学逻辑

有不少同学在明确读懂文段的字面意思的时候，却感觉摸不清信息之间的逻辑关系，从而在答题时遇到极大的困难。其实，只要我们充分回忆在小学时学过的一些数学逻辑，并且善用这些数学逻辑，就可以轻松破题了。下面小编要和大家带来的就是GRE阅读技巧之数学逻辑。

当我们看到如下一段文字：

Of the thousands of specimens of meteorites found on Earth and known to science, only about 100 are igneous; that is, they have undergone melting by volcanic action at some time since the planets were first formed. These igneous meteorites are known as achondrites because they lack chondrules—small stony spherules found in the thousands of meteorites (called “chondrites”) composed primarily of unaltered minerals that condensed from dust and gas at the origin of the solar system.

有这样的一道题目：

According to the passage, the presence of chondrules in a meteorite indicates that the meteorite

(A) has probably come from Mars

(B) is older than the solar system itself

(C) has not been melted since the solar system formed

(D) is certainly less than 4 billion years old

(E) is a small fragment of an asteroid

这道题目的答案为(C)：has not been melted since the solar system formed。当然，如果我们受困于文段中话语的表达形式，很可能很难找到答案。其实，我们应该把话语里的关键内容当作数学概念里的“量”或者“值”，然后梳理和提取逻辑如下：

首先，100 meteorites = （为什么是“等于”，因为文段的“are”这个be动词可以理解为“相等”关系）igneous。

然后，针对 igneous 有两个细节说明：

1、igneous =（为什么是“等于”，因为文段中是“that is”就是表达“相等”关系）meteorites have undergone melting。

2、igneous meteorites = （为什么是“等于”，因为“because”可以理解为“相等” 关系）lack chondrules。

此时，我们利用“等号的传递性”这个小学水平的数学概念，把个细节说明里的等号关系带入后可知：meteorites that have undergone melting lack chondrules。

那么，题干中所说的 the presence of chondrules in a meteorite 与 lack chondrule 相反。所以，选项C中的 has not been melted 因与 have undergone melting 相反，从而已经基本正确了。

至此，我们已经通过小学时学过的数学逻辑，基本找到了正确选项。

最后，我们在文段的最后找到 at the origin of the solar system 与 选项(C)中的 since the solar system formed。这里只是简单的文字小把戏而已。

以上就是小编为大家带来的GRE阅读技巧之数学逻辑。当我们在明确读懂文段的字面意思却感觉摸不清信息之间的逻辑关系时，我们可以借用一些简单基本的数学逻辑来实现轻松破题。这样的情况在GRE阅读中频繁出现，这样的破题方法在GRE阅读中有很广的适用性。