在GMAT 考试中，如果能够拿下句子改错（简称SC），就可以在Verbal部分取得优势，GAMT700 也就不会太难，由此可见SC在GMAT考试中是很重要的。很多同学也深知这一点，所以在SC部分花费了大量的精力，但是SC知识点太多，太杂，而且琐碎，以至于很多同学无处下手，今天我就帮大家总结一下SC考点。每一个考点我们会从占比、难度系数、例题讲解三个方面来展开。
1，GMAT考试SC句法结构 （占比：60%-70% 难度：基础）
句法结构是一个GMAT考试比较基础的考点，也是同学们去搞定长难句的核心，那句子结构是什么，看下面的等式：
句子 = 主干 修饰
句子的逻辑语义 = 主干意思 修饰关系
那么句法结构解决的就是主干的问题，这就想到了比较基本的5大简单句：
S V
S V O
S V O O
S V O C
S V P
在简单句的基础上，可以通过连词把句子变成合句和复句。
连词包括并列连词 & 从属连词，所以并列连词或者分号链接的是合句，从属连词链接的是复句。
这个时候GMAT考试就会来考察大家对于句子完整性的判断，对连词的使用，标点符号的使用等内容。
这里，给大家举个例子~
Neuroscientists, having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are now drawing solid conclusions about how the human brain grows and how babies acquire language.
A Neuroscientists, having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are
B Neuroscientists, having amassed a wealth of knowledge about the brain and its development from birth to adulthood over the past twenty years, and are
C Neuroscientists amassing a wealth of knowledge about the brain and its development from birth to adulthood over the past twenty years, and are
D Neuroscientists have amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood,
E Neuroscientists have amassed, over the past twenty years, a wealth of knowledge about the brain and its development from birth to adulthood,
选A
题目分析：
原句有点长，但主干很简单，去掉长长的插入语having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood，
主干为：
Neuroscientists are now drawing solid conclusions about how the human brain grows.
选项分析：
A选项：Correct. 本选项在语法和逻辑上均是正确的。
B选项：and是连词，需要连接两个句子。但在本选项中，and身前的句子没有谓语动词。
C选项：and身前的句子没有谓语动词错误同(B)。
D选项：主干和修饰互换，逻辑变。
E选项：主干和修饰互换，逻辑变。
2，GMAT考试SC修饰（占比：60% 难度：中等）
修饰包含四种修饰关系：定语、状语、同位语和插入语
在修饰当中，经常作为GMAT考试出题点的比如说：短语在句首；逗号doing在结尾，表结果或伴随。
举个例子：
By sucking sap from the young twigs of the hemlock tree, tree growth is retarded by the woolly adelgid, causing needles to change color from deep green to grayish green and to drop prematurely.
A tree growth is retarded by the woolly adelgid, causing needles to change color from deep green to grayish green and to drop
B tree growth is retarded by the woolly adelgid, and this causes the color of needles to change from deep green to grayish green, and their dropping
C the woolly adelgid retards tree growth, which causes needles to change color from deep green to grayish green, and dropping
D the woolly adelgid retards tree growth, causing needles to change color from deep green to grayish green and to drop
E the woolly adelgid retards tree growth, and this causes the color of needles to change from deep green to grayish green, and then their dropping
题目分析：
介词短语放句首做状语，要跟主句的逻辑主语形成合理的逻辑关系，根据语义是adelgid suck sap,所以主句主语因该是adelgid；定语从句修饰名词，doing放句末可做伴随状语或结果状语，修饰句子；
选项分析：
A选项.主语是tree growth不能发出suck sap这个动作，语义不合理；
B选项.同A，逻辑主语错误；添加连词and改变原句语义重心；
C选项.which引导非性定语从句修饰tree growth不合理；to change and dropping不平行；
D选项.正确，causing做结果状语；
E. 选项添加and改变原句语义重心。
3，逻辑（占比：50% 难度：中高等）
逻辑是一种关系，GMAT考试考的就是逻辑，在SC部分中体现的是句子的关系，句子与句子间的相互关系，一个句子内部的搭配关系和修饰关系。
举个例子：
Turning away from literary realism to write romantic stories about the peasant life and landscape of northern Sweden, in 1909 Selma Lagerl?f was the novelist who became the first woman and was also the first Swedish writer to win the Nobel Prize for Literature.
A Turning away from literary realism to write romantic stories about the peasant life and landscape of northern Sweden, in 1909 Selma Lagerl?f was the novelist who became the first woman and was also the first Swedish writer to win
B She turned away from literary realism and wrote romantic stories about the peasant life and landscape of northern Sweden, and novelist Selma Lagerl?f in 1909 became the first woman as well as the first Swedish writer that won
C Selma Lagerl?f was a novelist who turned away from literary realism to write romantic stories about the peasant life and landscape of northern Sweden, and in 1909 she became the first woman in addition to the first Swedish writer winning
D A novelist who turned away from literary realism to write romantic stories about the peasant life and landscape of northern Sweden, Selma Lagerl?f became in 1909 the first woman and also the first Swedish writer to win
E As a novelist, Selma Lagerl?f turned away from literary realism and wrote romantic stories about the peasant life and landscape of northern Sweden, in 1909 becoming the first woman and also the first Swedish writer that won
选项分析：
A选项：分词短语在句首，逻辑主语要立马给出，Selma Lagerl?f逻辑主语前家里时间状语不符合表达习惯。状语in 1909修饰其身后的句子Selma Lagerl?f was the novelist，这是不正确的。不能说SL这个人在1909年才成为小说家，而是SL一直是小说家，到了1909年才获奖。因此，1909应该修饰 Selma Lagerl?f became the first woman。且主干是SL是小说家，获奖做成了修饰，这个句子之间的主次关系不对，主干和修饰互换。
B选项：as well as虽然可以是连词，但其连接两者的后者在地位上要弱于前者，这点和and不同，and是纯粹的并列。在本题中，两个角色显然没有强弱区别，因此as well as需改为and。另外，She turned away from...and Selma Lagerl?f became...，and增加句子关系。

C选项：副词in addition to需改为并列连词and，became the first woman和was also the first Swedish write应具有并列关系。另外，and增加句子关系，该错误原理同(B)。
D选项：Correct. 本选项在语法和逻辑上均是正确的。
E选项：主次颠倒，逻辑语义变。
为了让大家能够清楚的明白和理解考点，每一个考点我都会从占比、难度系数、例题讲解三个方面来展开，因为GMAT考试SC部分涉及的考点比较多，所以集中在一篇来说信息量太大，所以今天就只给大家介绍三个知识点，我将会在下篇继续为大家讲解GMAT考试SC部分的考点总结。