"Žofie je studentkou na vysoké škole v Praze."

Translation: Žofie is a student at a university in Prague.

[Hugo647250]

This is a good example of a case that requires the indefinite article - she goes not to any old university, but one in Prague (though indefinite because we don't know which one).

[SBURNILL]

In the Czech Republic, can an establishment called "vysoká škola" also be called "univerzita", or is there a difference?

[endless_sleeper]

Not every 'vysoká škola' is a 'univerzita.'

[RickardHol3]

Why is it "Zofie je studentkou ..." and not "... studentka ..." ?

[Laurent103347]

I was told instrumental is often use in place of nominative when you mean that the qualification is permanent, or for jobs (she is a teacher : je učitelkou). It may be more bookish with instrumental, also.

[VladaFu]

I would not explain it this way. You most often use the nominative for some equivalence and the instrumental when A acts / functions as B.

[Gregor565424]

it is an university
Without an I was looking for other solutions

[BoneheadBass]

Actually, it is not "an university," it is "a university," as shown above. Although the word starts with a vowel, that vowel sounds like "yu" here and it requires "a" before the word.