OG 会有错吗？

bruins

对几道OG SC 题有疑问。
SC 211：
211. The period when the great painted caves at Lascaux and Altamira were occupied by Upper Paleolithic people [U]has been established by carbon-14 dating, but what is much more difficult to determine are [/U]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

这道题determine 后为什么是is 呢？ 后面跟的可是the reason..,the use.. and the meaning of.., 这难道不是复数形吗？

另外SC 218：
218. Despite protests from some waste-disposal companies, state health officials have ordered the levels of bacteria in seawater at popular beaches to be measured and that the results be published.
(A)the levels of bacteria in seawater at popular beaches to be measured and that the results be
(B)that seawater at popular beaches should be measured for their levels of bacteria, with the results being
(C)the measure of levels of bacteria in seawater at popular beaches and the results to be
(D)seawater measured at popular beaches for levels of bacteria, with their results
(E)that the levels of bacteria in seawater at popular beaches be measured and the results

按照它所说的 x ordered that y be z'ed 形式及parallel的要求，results后面是不是应该有be 呀？

实在是不明白，请大家点拨一下。Thanx.

princess

1.主谓一致，主谓一致，当然应该是看主语而不是宾语咯！
这儿的主语是一从句：what is much more difficult to determine，从句作主语，谓语用单数

2.牵涉到省略的问题
一般在并列结构中（用and, but等连接的句子），后一部分重复出现的助动词be可以省略
（lzm里面是这么说的吧）

tongxun

1、就是princess讲的：主谓一致。
2、这个be是可以省略的。

zyh79

what的规则是不是？
what is.....is
what are... are

tongxun

这里做主语的是整个what从句，而不是what。