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：
Doctors generally agree that such factors as cigarette smoking, eating rich foods high in fats, and alcohol consumption not only do damage by themselves but also aggravate genetic predispositions toward certain diseases.
(A) not only do damage by themselves but also aggravate
(B) do damage by themselves but also are aggravating to
(C) are damaging by themselves but also are aggravating
(D) not only do damage by themselves, they are also aggravating to
(E) are doing damage by themselves, and they are also aggravating
选项分析：
(A)not only do damage by themselves but also aggravate
【正确】 “not only do damage……but also aggravate”正确使用了“not only X but also Y”的平行结构。
【大意】 医生们一般同意吸烟，摄取高脂肪食物和酗酒不仅本身会造成损害，还会将遗传素质导向某些疾病。
(B)do damage by themselves but also are aggravating to
【错误】 见(A)。
(C)are damaging by themselves but also are aggravating
【错误】 见(A)。
(D)not only do damage by themselves, they are also aggravating to
【错误】 见(A)。
(E)are doing damage by themselves, and they are also aggravating
【错误】 见(A)。
解题思路：
有日常逻辑可知“do damage”和“aggravate”是递进关系，仅有(A)正确使用了“not only X but (also) Y”的平行结构，因此选择(A)。
