标题: 搞不清的形式主语it [打印本页] 作者: coocooper 时间: 2010-10-21 00:04 标题: 搞不清的形式主语it 真的不太弄得明白形式主语it到底指代的是什么，比如这个句子： Ozone, a special form of oxygen that screens out harmful ultraviolet rays, reaches high concentrations twelve miles above Earth, where it had long appeared immune to human influence, we have now realized, though, that emission of industrial cholorofluorocarbons deplete the ozone layer.
这个是正确答案填进去之后的句子，解释说这个it是形式主语，指代句子真正主语， 在句子的后部。。。 我的问题是，到底指代谁啊？ 怎么看形式主语的指代？ 谢谢！作者: pipi198906 时间: 2010-10-21 19:51
句子的形式主语应该是Ozone！ where it had long appeared immune to human influence在这里作为定语从句，应该是修饰 high concentrations twelve miles above Earth。 意思也就是说过去人们认为破坏不了大气层，但现在意识到错了！
而后面却说 我们意识到工业废气会破坏臭氧层。 显然逻辑不对。作者: coocooper 时间: 2010-10-21 20:35
如果指代human influence, 不是说human influence immune to human influence?作者: jbc88 时间: 2010-10-21 20:45
额，我错了。少了个to。指代to human influence 举个例子吧。
It was pretty hard for him to bring up the child on his own.
It+be动词+形容词+for sb.+to do sth.句型中，to do sth.做真实主语，it做形式主语，所以这句话中to bring up the child是真实主语，it是形式主语。was pretty hard 是谓语。for him 是宾语。作者: coocooper 时间: 2010-10-21 23:39
So the sentence from the original question should be :immune to human influence had long appeared?
S：本人是菜鸟，看GMAT才两周，不知道对不对！！不对的话就当是浮云吧~~~~~