This is by no means an extremely accurate rendering of Passive Voice in English, but I did manage to put together information, examples and tips from various sources which I hope may be useful for anyone trying to understand this grammar point.
Antonio Marchal de la TorreProfesor de inglés y jefe de estudios adjunto en IES Ingeniero de la Cierva em IES Ingeniero de la Cierva
18. Which object to transform into a subject depends on what you want to put the focus on. For drilling purposes, it is customary to use the first one:
25. I was shown her new house. (Note the Spanish “Me enseñósunueva casa.”)
26. Leaving aside focus or learning issues, in English the active Oi is usually preferred as the subject of the passive sentence (except with explain and suggest):