形式主语(先行主语)，形式主语it指代句子后真正主语
强调结构，It beV.+强调部分+who(m)或that+其它部分
强调结构中it不做句子结构中的任何成分，无所指代，故不与后面的it冲突
118. (30767-!-item-!-188;#058&004308)
It was only after Katharine Graham became publisher of The Washington Post in 1963 that it moved into the first rank of American newspapers, and it was under her command that the paper won high praise for its unrelenting reporting of the Watergate scandal.
这是之前的帖子,但是这题
8. (24773-!-item-!-188;#058&001691)
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
prep说第一个it是形式主语,怎么看出来的啊?
跟上面形式主语的结构又不一样
另外 强调结构中it不做句子结构中的任何成分，无所指代，故不与后面的it冲突
可是prep解释说:形式主语it只待了句子的真正主语,所以语后面的it指代不一致 到底哪一个才是对的啊 且若按楼上所讲,it指代Ozone 选项A的it指代就没错了 到底it在这里是指什么? 有没有人可以指点一下!!! | 
