英语语法问题

Question

Fidelity Investments Inc. found 41 percent of the 500 couples it surveyed disagree on whether both or at least one spouse will work in retirement .这个句子 it是作什么成分呢？能详细描述么？他是不是作形式主语啊，最好能够解释下为什么

Answer 1

这个it指代前面主语Fidelity Investments Inc,

it surveyed这里的成分是定语成分, 这里省略了引导词whom

idelity
Investments Inc. found 41 percent of the 500 couples (whom it
surveyed) disagree on whether both or at least one spouse will work in
retirement追问

在么？