2
votes
2answers
503 views

When to use “sein” and “haben” for verbs that allow both auxiliary verbs?

In some dictionaries, contrary to what Wiktionary states, one can find that, say, verderben allows both sein and haben as auxiliary verbs to form the Perfekt. That's the case for these verbs as well: ...
1
vote
1answer
90 views

Can adding a prefix change the auxiliary verb?

Usually, when I have to conjugate a verb with a prefix (not necessarily separable!) in Perfekt, I automatically associate the same auxiliary verb, say [verschwimmen, ich bin verschwommen] because ...