"Imperfect" as a tense of other languages (it's not a term usually used in English grammar) is often translated as a past progressive in English: "I was walking down the street", "he was thinking about it", etc. It could also be translated with "would" or "used to" to indicate habitual action. "He would come here every day" or "he used to come here every day".
Imperfect passive would be translated with a past passive progressive, something like "I was being audited" or "he was being given a second chance". It can sound a bit clunky in English, but that's the way you'd say it.
