Zwracano
Zwracano is a Polish verb form. It is the past passive participle, third-person plural, imperfective aspect of the verb "zwracać". This verb generally translates to "to return" or "to give back". Therefore, "zwracano" signifies that something was being returned or given back by multiple unspecified agents in the past. The imperfective aspect suggests that this action was ongoing or habitual, rather than a single completed event.
For example, in a sentence like "Pieniądze zwracano co miesiąc" (Money was being returned every month), "zwracano"
The form "zwracano" is a historical or literary form that is not commonly used in modern spoken