I'm having some trouble to find a definitive pattern in the Depersonal verbs, past tense.
I understand the conjugations with -ać, -eć to -ano (czytać > czytano)
My main issue is with -ić verb endings. They change to -iono or -to (bawić > bawiono and bić > bito). I feel that -bić ending verbs are the exception and I should follow the -iono ending with -ić verb endings
I've checked all my textbooks, dictionaries and Oscar Swan 'Polish in a nutshell', but have been unable to find the solution.
Thanks in advance,