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
請問一下菜鳥 OG的補充如下 ,是不是說WHAT 子句之後的動詞要用單數???如本題把are改成is,我不太懂也!
謝謝您的回覆!
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。
