This is the 470th most frequent Danish word.
hvilke
"Which" (plural).
Here, 'hvilke' is used as an interrogative pronoun to ask about a specific selection, in this case, books.
Hvilke bøger har du læst i år?
Which books have you read this year?
In this example, 'hvilke' is employed to refer to a set of films in a relative clause, expressing indecision about a choice.
Jeg kan ikke beslutte, hvilke film jeg vil se.
I can't decide which films I want to watch.
In this sentence, 'hvilke' serves to introduce a clause explaining the options being referred to.