急求助一道prep 谢谢了！

lllmmm

Those skeptical of the extent of global warming argue that short-term temperature data are an inadequate means of predicting long-term trends and point out that the scientific community remains divided on whether significant warming will occur and what impact will it have if it does.

(A) on whether significant warming will occur and what impact will it have if it does
(B) on whether warming that occurs will be significant and the impact it would have
(C) as to whether significant warming will occur or the impact it would have if it did
(D) over whether there will be significant warming or the impact it will have
(E) over whether significant warming will occur and what impact it would have

这题答案是E   我想问A为什么不对    还有E最后那个  would have是怎么回事   谢谢了！

2017

我认为：E选项后面是假设，假设发生了会怎么样，所以用would have （what impact)

lllmmm

那A为什么不对呢  请问

2017

A应该假设，应该也用would

mlvince

我觉得a的if it does和whether significant warming will occur 是重复的吧？