作者：英吉
The decline of the mountain yellow-legged frog in the high reaches of the Sierra Nevada has become severe enough for the United States Fish and Wildlife Service quite possibly to list it as an endangered species in the near future.
(A) severe enough for the United States Fish and Wildlife Service quite possibly to list it
(B) severe enough so that the United States Fish and Wildlife Service could well list them
(C) severe enough for it quite possibly to be listed by the United States Fish and Wildlife Service
(D) so severe that the United States Fish and Wildlife Service could well list it
(E) so severe that they could well be listed by the United States Fish and Wildlife Service
原文意思：一种青蛙的下降变得如此严重从而是美国政府把这种动物列入濒危物种
题目分析：有的选项用severe enough for有的用so severe 并且用that把导致的结果前后分开，显然加上that使得意思前后更清楚，前面是某些原因很严重而that后面就是导致的结果，A干掉。B用them，可这个them指的是frog，是个单数名词，不能用them，干掉。C没用that，干掉。D既用了that使前后分开而且后面用it，逻辑通顺，留着。E用they指frog，和B的错误类似，干掉！
