Breakdown of Mijn broer is vanmorgen wezen vissen.
zijn
to be
de broer
the brother
mijn
my
vanmorgen
this morning
Questions & Answers about Mijn broer is vanmorgen wezen vissen.
Why does this sentence use is ... wezen vissen instead of just heeft gevist?
The zijn + wezen + bare infinitive structure is special: it specifically means someone went out to do an activity and has already returned. Heeft gevist just means "has fished" and doesn't necessarily capture that he went on a short trip and came back.
Why do we use is as the helping verb here? Doesn't vissen normally use hebben?
Yes, a normal perfect tense would be hij heeft gevist. However, the wezen + infinitive structure is fundamentally built around the verb zijn (to be). Because of this, it always takes a form of zijn as its helping verb, which is is for mijn broer.
What exactly is the word wezen?
Wezen is an alternative infinitive form of the verb zijn (to be). In this sentence structure, it acts similarly to how we say "has been fishing" in English, though it translates more naturally to "went fishing". Notice that it sits where you might expect a past participle, but it keeps its infinitive shape.
Can I say deze morgen instead of vanmorgen?