OG 211

主句的谓语动词怎么判断？干吗用 is ？？因为主语是个句子？？

211. The period when the great painted caves at Lascaux and Altamira were occupied by

Upper Paleolithic people have been established by carbon-14 dating, but what is much

more difficult to determine is the reason for their decoration, the use to which primitive

people put the caves, and the meaning of the magnificently depicted animals.

菜鸟日记：

知识点——主谓一致：what 从句做主语时，主句的谓语动词形式由后面的名词决

定；如果what在what从句中做主语，它的谓语动词形式应该与主句的谓语动词形式

保持一致。/主语从句做主语只有这个例外，其他的都用单数谓语。

完全把我绕晕了，请高人指点，谢谢~~

ding~~

怎么没人回答呢？？