98-8北美13， 牛人请进

13 ____ of large mammals once dominated the North American prairies the American bison

and the pronghorn antelope.

(A) There are two species

(B) With two species

(C) Two species are

(D) Two species

答案是D，没有问题，但这句话的结构是怎样的呢？觉得读不通，如果once dominated the North American prairies 修饰主语的话，这句话应该是 Two species of large mammals once dominated the North American prairies were the American bison and the pronghorn antelope，对吗？

D is correct.  simplifying the sentence:  two species once dominated the North American prairies.

dominated 是胃语

the American bison and the pronghorn antelope. 是  two species 的主语补足语

我怎么觉得Two species of large mammals once dominated the North American prairies the American bison and the pronghorn antelope.里the American bison and the pronghorn antelope是two species的同位语，只是因为太长所以後置了。

Two species of large mammals，the American bison and the pronghorn antelope， once dominated the North American prairies. 我觉得正确的顺序是这样的。