jellei- i completely misunderstood the lesson at first, and your comment to ziggy69 helped clarify for me. unfortunately i sent in a report (now in error), so i should have checked here first before sending the error report (which should be ignored but i don't know how to retract it).
Moreover when there's a particular word in English sentence, it should be translated not omitted unless translation has the same meaning without it. In this case "to have" means "mieć, posiadać (na własność, być właścicielem - to own it (the property), to be an owner), so it's rather important imho.
Does mieć mean to own as in to be the owner of something or does it have the wider meaning of to have.
Eg I have a company car. I don't own it.