I have seen a bus yesterday.的被动语态

问题描述:

I have seen a bus yesterday.的被动语态

I have seen a bus.的被动语态
A bus have been seen by me.
I saw a bus yesterday.的被动语态
A bus was seen yesterday.

A bus was seen by me yesterday.

a bus has been seen yesterday

A bus has been seen yesterday
语法是不是有问题啊?

A bus was seen by me yesterday.
被动语态:be+p.p.