Auxiliary verbs are used to form Tenses / Zeiten, the Passive or the Conjunctive.
Example:
ich habe gegessen (Perfekt) - I have eaten
ich werde gehen (Futur I) - I will go
~ haben / to have
~ sein / to be
~ werden / to become
“lassen” - to let is not a “real” auxiliary verb, but it partly takes the functions of an auxiliary verb.
Modal verbs can be regarded as auxiliary verbs in a broader sense, because they also modify other verbs.
Modal verbs modify verbs by giving them gradations of feeling, that means they modify without completely changing the meaning.
~ dürfen / to be allowed to do
~ können / can
~ möchten / would like
(~ mögen / like)
~ müssen / must
~ sollen / should
~ wollen / want to
more information: info@longua.org
LONGUA.ORG: languages.li, longua.org in Italien, longua.org in Deutschland, longua.org in China, B1-Test (Schweiz), B2-Test (Schweiz), Allemand à Munich.ch, Soggiorni in Germania.it, Apprendre Allemand, 木木杨的博客 - China