Model: fallen
Auxiliary: sein
Other forms: ausfallen/nicht ausfallen
Irregular conjugation for ther verb "fallen" and its compounds: stem vowel mutation (umlaut) in singular form of the second and third person in Present tense ("du fällst").There is a vowel change in the stem of Present tense ("ich falle") and the stem of Preterite ("ich fiel") and the stem of Past Participle ("gefallen").
Präsens
Präteritum
Perfekt
Plusquamperfekt
Futur II
Futur I