同学你好，该知识点来自沪江网校《英语零基础直达大学六级【3年随心畅学班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好～
it is reported that the thief has been arrested
相当于that the thief has been arrested is reported
主语是主语从句that the thief has been arrested，谓语是is reported
the thief 是从句的主语。

the thief is reported to have been arrested
这里to have been reported是主语补足语，相当于主动语态中的宾语补足语。

祝同学学习进步～