GMAT语法题，又称句子改错题(sentence correction)，是整个GMAT考试中对考生英语语法能力考查要求最高的题型，也往往是中国学生最为头疼的一类题目。没有扎实的语法基础和一定的逻辑分析能力，想要做好语法题难度极高。怎样做好GMAT语法题?下面小编就通过一些经典真题的实例解析，为大家全面讲解GMAT语法题的解题思路和方法技巧。
实例题目：
Paleontologists believe that fragments of a primate jawbone unearthed in Burma and estimated at 40 to 44 million years old provide evidence of a crucial step along the evolutionary path that led to human beings.
(A) at 40 to 44 million years old provide evidence of
(B) as being 40 to 44 million years old provides evidence of
(C) that it is 40 to 44 million years old provides evidence of what was
(D) to be 40 to 44 million years old provide evidence of
(E) as 40 to 44 million years old provides evidence of what was
选项分析：
(A)at 40 to 44 million years old provide evidence of
【错误】 固定搭配：“be estimated at”无此搭配。
(B)as being 40 to 44 million years old provides evidence of
【错误1】 固定搭配：“be estimated as being”无此搭配。
【错误2】 主谓一致：“provides”的主语的核心词是“fragments”主谓不一致。
(C)that it is 40 to 44 million years old provides evidence of what was
【错误1】 主谓一致：见(B)中(2)。
【错误2】 固定搭配：不存在“estimated(被动)that……”的用法，因为语法上“that”引导的名词性从句做不了“estimated”的宾语，因为“estimated”是被动形式。
(D)to be 40 to 44 million years old provide evidence of
【正确】 “fragments”和“provide”正确地满足了主谓一致，“estimated to be”是正确的固定搭配。
(E)as 40 to 44 million years old provides evidence
【错误】 主谓一致：见(B)中【错误2】。
解题思路：
“provides”和“fragments”主谓不一致，立即排除(B)、(C)和(E)。即使不确定(A)选项“be estimated at”是否正确，也可以确定“be estimated to be”必然没有错误，因此选择(D)。
