it's amazing how much this helped是什么结构

it's amazing how much this helped是什么结构
it's amazing how much this helped是什么结构

it's amazing how much this helped是什么结构
it作形式主语,指代实际的主语从句how much this helped.
如果把主语从句how much it helped放在主语的位置,那这个句子主语太长、谓语部分(is amazing)太短,头重脚轻了,为了使句子平衡,就用it作了形式主语,把实际的主语放在后面了.
这个结构可以总结为：
It is +形容词/名词 +主语从句/不定式/动名词.
eg:It is necassary that we should learn English.
It is necessary (for us) to learn English.
It is no use arguing with him.

it is +adj。结构

这是一个主语从句，句中it做形式主语，真正主语是后面的how much this helped
原句应该是how much this helped is amazing。
希望你能看懂 祝你学习愉快

用it 作形式主语的主语从句。 该句原句为 How much this helped is amazing .将主语how much this helped 放在末尾，用it做形式主语，可以避免句子结构头重脚轻。

是宾语从句