请教一个英语语法问题？

Question

Password comparison is when the password supplied by the user is compared with the one stored in the repository.
请问这句话的句子成分如何划分？请详细说明一下，谢谢

Answer 1

这是个主系表结构的句子，主语是passeword comparison，系动是is，when…至结束是表语从句。

Answer 2

主干：
Password comparison is + when引导的从句。
从句主干：
the password is compared