GMAT考试中句子改错题总是让大家一头雾水，到底应该如何应对这类题目，如何把这个单项快速提升，武汉新东方学校和你一起学习。

　　Part1

　　在国内GMAT培训中往往把Sentence Correction(句子改错)单项叫做“语法”，这导致了很多学生对这个单项的理解误区，以为这个单项的核心是在考察语法知识，其实SC这个单项的核心是句子意思，在我看来，SC的考试思想是：句子意思是“blueprint”，语法是“tools”;做题思路应该是：句子意思决定句子结构，学生在读懂句子的基础上，能运用合理的语法结构来表达这个句子意思。所以很多句子改错的难题并不是难在语法上，而是难在句子意思上，有些题目存在多个语法正确的选项，但是表达的句子意思却是不同，如果学生能从句子意思而不是语法入手，题目就能迎刃而解。

　　举例：

　　Although I believe that you are right, I need time to consider. (尽管我相信你是对的，我还是需要时间考虑)

　　Although I need time to consider, I believe that you are right.(尽管我需要时间考虑，我相信你是对的)

　　上述两个句子的语法都完全正确，但是表意却完全不同，究其原因，就是句子主干不同。英语表达中分句子主干和修饰成分，作者主要想表达的核心内容就是句子主干，如果随意改变句子主干，其实就是在改变原文作者想要表达的句子意思。所以，我认为如果当原文主干逻辑语义和基本结构不存在问题的时候，我们应该遵从原文语义保留原文句子主干。下面我们来看一道OG上的题目：

　　Even though Clovis points, spear points with longitudinal grooves chipped onto their faces, have been found all over North America, they are named for the New Mexico site where they were first discovered in 1932.

　　(A) Even though Clovis points, spear points with longitudinal grooves chipped onto their faces, have been found all over North America, they are named for the New Mexico site where they were first discovered in 1932.

　　(B) Although named for the New Mexico site where first discovered in 1932, Clovis points are spear points of longitudinal grooves chipped onto their faces and have been found all over North America.

　　(C) Named for the New Mexico site where they have been first discovered in 1932, Clovis points, spear points of longitudinal grooves chipped onto the faces, have been found all over North America.

　　(D) Spear points with longitudinal grooves that are chipped onto the faces, Clovis points, even though named for the New Mexico site where first discovered in 1932, but were found all over North America.

　　(E) While Clovis points are spear points whose faces have longitudinal grooves chipped into them, they have been found all over North America, and named for the New Mexico site where they have been first discovered in 1932.

　　这是一道全划线的题目，对于全划线的句子最重要的就是先抓住原文句子想要表达的句子意思，也就是说第一步是抓住原文句子主干，如果原文句子主干表意逻辑上没有问题，那么我们是要遵从原文语义保留原文句子主干。

　　原文句子主干：they (Clovis points) are named for the New Mexico.

　　也就是说原文表达的重点是C是因何命名的。整句话的结构是：让步状语从句，主句;原文整体表意：尽管C在北美到处都被发现，他们是因他们的发现地而命名。

　　这道题目是一道典型的语义题，B选项语法完全正确，但是表达的意思却不正确。

　　B选项表意：尽管因发现地而命名，C在整个北美都可以被发现。

　　本质上来说，就是因为B选项改变了原文的句子主干，导致了语义上的错误。而CDE三个选项的表意也都不正确。所以该题最快的解题思路就是从句子意思入手。

　　关于句子整体表意的测试在GMAT SC中非常常见，在Part2部分我们也会进一步讨论。

　　Part2

　　在这部分，我将在Part1的基础上继续用OG中的例子讨论句子主干对于句子语义的影响。

　　1、Neuroscientists, having amassed a wealth of knowledgeover the past twenty years about the brain and its development from birth toadulthood, are now drawing solid conclusions about how the humanbrain grows and how babies acquire language.

　　(A) Neuroscientists, having amassed awealth of knowledge over the past twenty years about the brain and itsdevelopment from birth to adulthood, are

　　(B) Neuroscientists, having amassed awealth of knowledge about the brain and its development from birth to adulthoodover the past twenty years, and are

　　(C) Neuroscientists amassing a wealth ofknowledge about the brain and its development from birth to adulthood over thepast twenty years, and are

　　(D) Neuroscientists have amassed awealth of knowledge over the past twenty years about the brain and itsdevelopment from birth to adulthood,

　　(E) Neuroscientists have amassed, overthe past twenty years, a wealth of knowledge about the brain and itsdevelopment from birth to adulthood,

　　长句子长划线，划线部分包含句子主干，所以第一步还是确定句子主干。这道题句子主干完整的选项是ADE三个选项;BC两个选项划线部分尾端出现了连词+动词，但是前面却没有谓语动词可以与之并列，所以BC两个选项句子结构不完整。

　　ADE三个选项最明显的区分点就是句子主干不同：

　　A选项句子主干：Neuroscientists are now drawing solidconclusions. A选项整体表意是：在过去二十年积累很多相关知识的基础上，神经科学家现在正在得到关于XX和XX的确实结论。

　　DE选项句子主干：Neuroscientists have amassed a wealth ofknowledge. DE选项整体表意是：神经科学家在在过去二十年积累了很多知识，得到了关于XX和XX的确实结论。

　　很明显DE两个选项转移了原文所要表达的中心思想，改变句子意思，而这种改变是没有道理的，因为原文的逻辑语义没有任何问题。

　　那么什么叫做原文语义有问题呢?请看下面一道OG上的例题：

　　In Emily Dickinson’s letters to Susan Huntington， Dickinson were written overa period beginning a few years before Susan’s marriage to Emily’s brother andending shortly before Emily’s death in 1886, outnumbering her letters to anyone else.

　　(A) Dickinson were written over a periodbeginning a few years before Susan’s marriage to Emily’s brother and endingshortly before Emily’s death in 1886, outnumbering

　　(B) Dickinson were written over a periodthat begins a few years before Susan’s marriage to Emily’s brother and endedshortly before Emily’s death in 1886, outnumber

　　(C) Dickinson, written over a periodbeginning a few years before Susan’s marriage to Emily’s brother and that endsshortly before Emily’s death in 1886 and outnumbering

　　(D) Dickinson, which were written over aperiod beginning a few years before Susan’s marriage to Emily’s brother, endingshortly before Emily’s death in 1886, and outnumbering

　　(E) Dickinson, which were written over aperiod beginning a few years before Susan’s marriage to Emily’s brother andending shortly before Emily’s death in 1886, outnumber

　　这道题题目的出题思路和考察点和上一道题目非常像，也是长句子长划线，划线包含句子主干，同样也存在句子主干结构有问题的选项，B选项两个谓语(were written和outnumber)之间没有连词连接，run-on;CD两个选项没有谓语，fragments。剩下AE两个选项最主要的区别依旧是句子主干不同。

　　A选项主干：Emily Dickinson’s letters to SusanHuntington Dickinsonwere written over a period. 句子整体表意：ED给SHD的信是在某个时间段内写的，超过了她给其他人写的。

　　E选项主干：Emily Dickinson’s letters to SusanHuntington outnumber her letters to anyone else. 句子整体表意：ED在某段时间段内给SHD写的信要比她给任何一个人写的信都多。

　　两个选项的侧重点依旧不同，但是这道题就难在原文的逻辑语义有问题，需要修正，也就是说原文主干强调的是信是在哪个时间段内被写的，而这很明显应该是修饰成分，正确的表达方式应该是E选项。

　　Takeaways:

　　1. 对于长句子长划线划线包含句子主干的题目来说，第一步一定要能读懂大概的句子意思，找到句子主干，不要一开始就纠结于句子内部的细枝末节，要有大局观。

　　2. 如果原文主干在逻辑语义上和语法结构上都没有问题，则我们应该遵从原文语义保留原文句子主干(常见情况);但是如果原文逻辑语义有误，则我们要对于原文的句子主干进行修正(相对少见)。