IT在此句中做什么?

来源:百度知道 编辑:UC知道 时间:2024/05/16 01:52:37
It was not until the 18th century that man realized that the whole of the brain was involved in the workings of the mind.问it是什么意思,是形式主语么?这句话的句子结构怎么分析,比如说,这句话有几个从句,都什么是主语宾语表语之类的,谢谢

it不是形式主语,这个句子是强调句句型,句子变形之前是Man did not realize that the whole...mind until the 18th century.本句强调的句子成分为状语until the 18th century,not须提前。realized that后面是个宾语从句

这是not ...until 结构的强调句型,第二个that引导的是宾语从句