Der Aufenthalt dauert drei Tage.

Because Aufenthalt is a masculine noun in German, so its nominative singular article is der.

You usually have to learn the grammatical gender together with the noun:

• der Aufenthalt = the stay
• not die Aufenthalt
• not das Aufenthalt

In this sentence, der Aufenthalt is the subject, so it stays in the nominative case: der Aufenthalt.

Because the subject is der Aufenthalt, which is third person singular.

The verb dauern means to last. Its present-tense forms include:

• ich dauere
• du dauerst
• er/sie/es dauert
• wir dauern
• ihr dauert
• sie/Sie dauern

Since der Aufenthalt is singular, German uses dauert:

• Der Aufenthalt dauert drei Tage.

Because after numbers, German often uses the noun without an article.

So:

• drei Tage = three days
• zwei Wochen = two weeks
• fünf Minuten = five minutes

That is completely normal. You do not need something like die drei Tage here.

Note that die drei Tage would mean the three days, which is more specific.

It is in the accusative case, because it functions as a measure of time/duration.

With dauern, the length of time is usually expressed in the accusative:

• Der Film dauert zwei Stunden.
• Die Reise dauert eine Woche.
• Der Aufenthalt dauert drei Tage.

In the plural, Tage looks the same in nominative and accusative, so you do not see a change here. But grammatically, it is accusative.

German often uses dauern where English uses last:

• The stay lasts three days.

That is the most direct German structure here.

German can also use other expressions, for example:

• Der Aufenthalt ist drei Tage lang.

That also works, but dauern is very common and natural for talking about duration.

Not normally. That sounds incomplete in German.

If you want to use sein, you usually need lang:

• Der Aufenthalt ist drei Tage lang.

Without lang, German strongly prefers:

• Der Aufenthalt dauert drei Tage.

So for learners, the safest choice is:

• use dauern for duration
• or use sein + ... lang

This is a normal German main clause, where the conjugated verb comes in second position.

Structure:

• Der Aufenthalt = subject
• dauert = conjugated verb
• drei Tage = time expression showing duration

So the pattern is:

• Subject + verb + rest

German is a verb-second language in main clauses. That means the finite verb usually comes second, even if something else comes first.

For example, you could also say:

• Drei Tage dauert der Aufenthalt.

That is also correct, but the verb dauert still stays in second position.

Not exactly.

• Aufenthalt = stay, period of staying somewhere
• Reise = journey, trip, travel
• Besuch = visit

So Aufenthalt focuses on the time spent in a place, not the trip itself.

For example:

• Die Reise dauert drei Tage. = the trip lasts three days
• Der Aufenthalt dauert drei Tage. = the stay lasts three days

Those are related ideas, but not the same.

The singular is der Tag = the day.

Plural:

• ein Tag = one day
• zwei Tage = two days
• drei Tage = three days

So Tage is simply the plural form of Tag.

Not in this sentence.

With dauern, German normally uses a direct duration expression:

• Der Aufenthalt dauert drei Tage.

If you say für drei Tage, that usually means for three days in a different sense, often with verbs like booking, planning, renting, or going somewhere:

• Ich buche ein Hotel für drei Tage.
• Wir bleiben für drei Tage in Berlin.

So:

• dauert drei Tage = lasts three days
• für drei Tage = for three days

They are related, but they are not interchangeable.

A rough English-friendly guide is:

OWF-ent-halt

A few tips:

• Au sounds a bit like ow in now
• auf sounds like owf
• ent is short and clear
• halt sounds close to English halt, but with a German a

The stress is on the first syllable:

• AUF-ent-halt

So the strongest part is AUF.