prep-1-123 定语从句单复数？

hh7920

123.       (30997-!-item-!-188;#058&004357)

 

According to two teams of paleontologists, recent fossil discoveries in Pakistan show that
whales, porpoises, and dolphins are more closely related to some of the
oldest known even-toed ungulates--a group of hoofed mammals that today
includes cows, camels, pigs, and hippos--than to any other mammals.

 

(A)
that whales, porpoises, and dolphins are more closely related to some
of the oldest known even-toed ungulates--a group of hoofed mammals that
today includes cows, camels, pigs, and hippos--than

(B)
that whales, porpoises, and dolphins are more closely related to some
of the oldest known even-toed ungulates--a group of hoofed mammals that
today include cows, camels, pigs, and hippos--as

(C)
whales, porpoises, and dolphins to be more closely related to some of
the oldest known even-toed ungulates--a group of hoofed mammals that
today include cows, camels, pigs, and hippos--than they are

(D)
whales, porpoises, and dolphins as being more closely related to some
of the oldest known even-toed ungulates--a group of hoofed mammals that
today includes cows, camels, pigs, and hippos--as they are

(E)
whales, porpoises, and dolphins as more closely related to some of the
oldest known even-toed ungulates--a group of hoofed mammals that today
include cows, camels, pigs, and hippos--than

答案是A,跟其他选项相比确实A更好。

可是mammals后不是改用include吗？为什么这里includes也对呢？是这里打错了还是单复数都可以？

prep里其他很多题目都指明定语从句修饰紧接的名词啊！

请牛牛指教啊～

        

AlienX

hoofed mammals include cows, camels, pigs and hippos好像邏輯不對 - 哺乳動物包含一些動物
應該是一組哺乳動物包含一些動物