885-17-22

windcolour

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（B）

(E) are established by carbon-14 dating, but that which is much more difficult to determine is

在A与B中我选了A.主语是"the reason for their decoration, the use to which primitive people put the caves, and the meaning of the magnificently depicted animals.

" 谓语动词不应该用复数吗

gre0426

"The reason for their decoration, the use to which primitive people put the caves, and the meaning of the magnificently depicted animals" is not the subject but the predicate. The subject is "what is much more difficult to determine", so the verb should be "is", not "are".