In the passive sentences, the main focus is put on the action, not the agent who does it. Let's see how passive sentences are formed.
Active Voice: a Reminder
Rule 1: "Regular" sentences in German are set in active voice. That means, the subject of the sentence acts, it carries out an action.
Passive Voice: Usage
Rule 2: In the passive voice it's not the subject who acts, but rather the thing or person that something happens to. The action is the relevant part, and the agent of the action is often left out.
We can use passive voice in all tenses.
In German, passive voice is used more frequently in written speech rather than in oral conversations.
Forming the Passive Voice
Rule 3: We form the passive with the auxiliary werden and the past participle of the main verb.
Rule 4: We can add "von X" to say "by X." Remember that in that case, the past participle of the main verb stands in the last position in the sentence.
Rule 5: To use passive voice in different tenses, you have to conjugate the auxiliary verb werden.
Passive Voice Substitute: Man
Rule 6: Germans often use active-voice substitutes to avoid using passive voice. One of the common ways to do so is to use the word man (one). This way, we don't focus on the agent of the sentence, since man is no one in particular, and still are able to talk about the action without using passive voice.
Of course, this word can be used in different variations: