GMAT语法主谓一致之What从句做主语也许很多考生还不是很熟悉，那么GMAT语法中What从句做主语是怎样来考察的呢?今天小编就结合例题为大家详细分析一下。
一、主谓一致中What从句做主语考点分析。
主谓一致中What从句做主语主要考察点在：What从句做主语时，to do, doing，谓语为单数。比如“What I said was right.”就是What从句做主语，从句做主语时谓语动词用单数。类似的情况还有to do不定式和doing形式做主语时，谓语动词也用单数。举例如，“To see is to believe/ Seeing is believing.”下面我们来看一道例题。
二、例题解析。
为了帮助大家更好地理解和掌握GMAT语法主谓一致之What从句做主语的考法，前程百利小编为大家分析一道经典例题。
The period when the great painted caves at Lascaux and Altamira were occupied by Upper Paleolithic people has been established by carbon-14 dating, but what is much more difficult to determine are the reason for their decoration, the use to which primitive people put the caves, and the meaning of the magnificently depicted animals.
(A) has been established by carbon-14 dating, but what is much more difficult to determine are
(B) has been established by carbon-14 dating, but what is much more difficult to determine is
(C) have been established by carbon-14 dating, but what is much more difficult to determine is
(D) have been established by carbon-14 dating, but what is much more difficult to determine are
(E) are established by carbon-14 dating, but that which is much more difficult to determine is
答案：B
解析：通过简化结构，我们发现“when”引导的从句可以省略不读，剩下的部分为“The period ____ been established by……”因为主语“The period”为单数，所以谓语动词用单数，排除选项C/D/E。选项A和选项B的区别在于逗号后的what从句后的谓语动词用单数还是复数的问题。根据以上讲解的GMAT语法主谓一致之What从句做主语的考点我们得知，What从句做主语谓语动词用单数。选项A排除。正确答案为B。
GMAT语法主谓一致之What从句做主语前程百利小编就为大家讲到这里了，当然还有很多What从句做主语的考点例题，大家可以抽时间来练习一下。相信通过练习能够慢慢掌握方法，条件反射式地反应出题目的考察目的。祝大家GMAT考试取得好成绩。
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