It was too dark for her to see anything.句子成分划分.

为你解答.
It was too dark for her to see anything.
对她来说,光线太暗,什么也看不见.
句子成分划分：这是个主系表结构的句子.
形式主语：it
真正的主语：to see anything
系动词：was
表语：too dark
状语：for he

并非楼上所言
这里并不是楼上所指的典型句型，而是：
It【形式主语】 was 【系动词】too dark【表语】 for her【介词短语作状语】 to see anything【结果状语】.
主干即【It was too dark.】
楼主认可吗？希望帮助到你！
竖子不足与谋！

It was too dark for her to see anything.
形式主语 be动词 表语 状语 主语 宾语