Could have been who helped Suny get her work done?

题目

Could have been who helped Suny get her work done?
Could have been who helped Suny get her work done?
A they...it B they...them C it...them D it...they
选什么？为什么？

答案

c 因为这里的it 是形式主语代替后面的真正主语they
还原成陈述句it could have been them who helped suny get her work done.