The German has an alternative to the passive voice that has an anonymous subject called man. Then the sentences are not actually in the grammatical form of passive voice but active voice. Only that still the subject (Who's doing it) is unknown. There is actually no direct English equivalent to this kind of passive. Quite often the English uses then "they" without actually saying who they are. Sometimes the it's said also: one would say... The one is in this case also a much unknown subject. Or you might be used as well. Still never quite the same

a) The house was sold.   They have sold the house.     a) Das Haus wurde verkauft.     Man hat das Haus verkauft.     b) The houses were sold.     They have sold the houses.     b) Die Häuser wurden verkauft.     Man hat die Häuser verkauft.

If you are familiar with French, there is the "on" that has the same function like the German man.

Man can be used in all kind of situations. Above we had a classic passive voice. Here we have some more examples.

Examples phrase without a subject     It was talked about a lot. They talked a lot about it. (whoever they are)     Es wurde viel gesprochen. Man sprach viel.   phrase with anonymous subject and human object       The boss was called.   They called the boss.     Der Chef wurde gerufen. Man rief den Chef.   The bosses were called.   They called the bosses.     Die Chefs wurden gerufen. Man rief die Chefs.   general statements         ---- *   In summer they swim.     Im Sommer wird geschwommen. Im Sommer schwimmt man.

Some more examples     Man gibt viel Geld für Miete aus. = A lot of money is spent on rent.   Man spricht nicht mehr mit ihm. = They do not talk to him anymore.   Ich weiß nicht, was man jetzt machen soll. = I do not know what to do now.