Outwardly,I was everything a well-brought up girl should be.这句话里should be是个什么语法

帮你分析一下句子结构：
Outwardly(状语,不需考虑),I was everything (句子主要结构)+定语从句 (that) a well-brought up girl should be--Should be 后面应该是替代everything的that,但是that在这里作为宾语可以省略的!