GMAT语法考试中句子改错题型对于很多考生来说是一个难题，结合具体的实例来攻克这一难关是一个很好的方法，今天小编就通过具体实例来给大家详细介绍一下。
1. In a review of 2,000 studies of human behavior that date back to the 1940s, two Swisspsychologists, declaring that since most of the studies had failed to control for such variables as social class and family size, none could be taken seriously.
(A) psychologists, declaring that since most of the studies had failed to control for such variables as social class and family size,
(B) psychologists, declaring that most of the studies failed in not controlling for such variables like social class and family size, and
(C) psychologists declared that since most of the studies, having failed to control for such variables as social class and family size,
(D) psychologists declared that since most of the studies fail in controlling for such variables like social class and family size,
(E) psychologists declared that since most of the studies had failed to control for variables such as social class and family size,
答案解析：
(A)psychologists, declaring that since most of the studies had failed to control for such variables as social class and family size,
【错误】 句子结构：本选项中“declaring”不能单独做谓语动词，于是“two Swiss psychologists”在主句中失去了谓语动词，主谓结构不完整。
(B)psychologists, declaring that most of the studies failed in not controlling for such variables like social class and family size, and
【错误1】 句子结构：见(A)。
【错误2】 固定搭配：“like”在标准书面英语中可以表示名词之间的相似性，不可以用于举例，“like”、“such like”用于举例是必错搭配。
(C)psychologists declared that since most of the studies, having failed to control for such variables as social class and family size,
【错误】 句子结构：“declared that”的后方应连接一个从句，这个从句中主语应该是“most of the studies”， “having failed”本应是其谓语动词，但语法上无法实现，因此“most of the studies”失去了谓语动词，主谓结构不完整。
(D)psychologists declared that since most of the studies fail in controlling for such variables like social class and family size,
【错误1】 动词时态：不同动词之间的时态差异需要合理解释，“declared是过去式而“fail”是一般现在时，此差异不存在合理解释。
【错误2】 固定搭配：见(B)中【错误2】。
(E)psychologists declared that since most of the studies had failed to control for variables such as social class and family size,
【正确】 “psychologists declared”构成主句的主谓结构，“that”引导从句，从句的主谓结构是“none could be taken seriously”，而“since most of the studies had failed to control for variables such as social class and family size”是从句的原因状语从句
【大意】 心理学家宣称，因为大多数研究无法控制如社会等级和家庭大小等变量，没有研究能被严肃对待。
【最优解题思路推荐】
(B)和(D)使用了错误搭配，立即排除。
(A)与(C)句子结构错误，立即排除。
因此选择(E)。
TIPS：对知识点的把握不够深入
GMAT语法要求我们选出一个最佳答案，这个最佳答案有可能是几个正确选项中选一个最好的(高个儿中选最高的)，也可能是在几个都不是完美的选项中选出相对较好的(矮子里选高个儿)，所以我们在解题时一定要把相对较大的错误和相对较小的错误区分开，首先应该把含有相对较大错误的选项排除，在含有相对较小错误的选项里面选一个相对较好的答案。而大家往往是能看出有两个错误，但不能区分哪个是相对较大，哪个是相对较小，因此在排除干扰选项时产生错误。事实上，在一道题目里的相对大错可能在另外一道题目里是小错，只有通过大量的练习才能提高对大小错误的把握和理解。
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GMAT语法考试解题规律浅析 http://gmat.zhan.com/tifen/30618.html
