가정법 도치 관련인데요...;;

If I were to be young again, I would be a teacher.
-> Were I to be young again, I would be a teacher.

가능한가요?

It is time that you should go to bed.
It is time that you went to bed.
둘 다 "~를 해야할 시간이라"고 해석되잖아요...

위 두 문장의 차이점은 뭔지...요...??