Model: geschehen
Auxiliary: sein
Other forms: geschehen
Irregular conjugation for the verb "geschehen": replacement of -e- in the stem of Present tense with -ie- for the second and third person singular form of Present tense, and with -a- for the Preterite ("es geschah") (Past Participle:"geschehen").
Präsens
Präteritum
Futur I
Perfekt
Plusquamperfekt
Futur II