I've just learnt about inversion and I'm not sure if it can be used in sentences which are in present simple or past simple. Can the two following sentences I made be inverted?
1a. The lawn was mowed yesterday.
1b. Yesterday was the lawn mowed.
2a. The streets are cleaned at night in Germany.
2b. In Germany are the streets cleaned at night.
I also think that my problem can be that I'd like to invert passive sentences. I'm quite confused.