Model: helfen
Auxiliary: haben
Other forms: nicht helfen
Irregular conjugation: replacement of -e- in the stem of Present tense with -i- for the second and third person singular form of Present tense and singular form of Imperative , and with -a- for Preterite ("ich half") and with -o- in Past Participle ("geholfen").
Präsens
Präteritum
Futur I
Perfekt
Plusquamperfekt
Futur II
zu + Infinitiv