Passive : "had been"

Question

The examples of use of the passive voice use is, will be, would be, was and used to be.  Please provide an example of "had been".  Is it for example "La souris avait été par le chat"?

Accepted Answer

Le P. 
You have left out a past participle in your example. I think you meant to write  ‘ … avait été mangé par .. ‘, in keeping with the lesson example. 
The lesson you linked is on simple tenses. 
The link below covers compound tenses
 https://progress.lawlessfrench.com/revision/grammar/how-to-form-the-passive-voice-with-compound-tenses-la-voix-passive