一个句子中的同一个代词多次出现，一定要指代相同的东西吗？

rainbowmanutd

RT 比如一个句子中it出现2次，2个it一个是形式主语，一个是代词，指代前面的某个东西，2个代词指代不一样，是不是这个句子就是错的？
比如这个题目。
Ozone, a special form of oxygen that screens out harmful ultraviolet rays, reaches high
concentrations twelve miles above Earth, where it has long appeared that it was immune from
human influence; we have now realized, though, that emissions of industrial chlorofluorocarbons
deplete the ozone layer.

(A) has long appeared that it was immune from
(B) has long appeared to have been immune from
(C) has long appeared as being immune to
(D) had long appeared immune to
(E) had long appeared that it was immune to  

选D，答案A就说2个it指代不一致。

dphxmg

The word, it, refers to two different concepts, indeed. Moreover, the past tense isn't appropriate, either, even if everything else is OK. Finally, the structure is awkward.