Breakdown of Vi vil gerne vide hvem der tændte sirenen.
vi
we
hvem
who
ville
want to / will
gerne
gladly / would like to
Questions & Answers about Vi vil gerne vide hvem der tændte sirenen.
Why is there a der after hvem in this sentence?
This is the rule for indirect questions. When a question word like hvem (who) or hvad (what) is the subject of an indirect question—meaning it represents the person or thing doing the action—you must insert the dummy subject der. Since "who" is the one turning on the siren here, we need der.
Would I still use der if the sentence was "We would like to know who you saw"?
No, you wouldn't. If the question word is the object rather than the subject, you do not use der. You would just say: Vi vil gerne vide, hvem du så. You only add der when the question word itself is the one performing the action in that part of the sentence.
Why use vil gerne instead of just vil to mean "want"?
By itself, vil means "want to" or shows a strong intention. Adding gerne (gladly) softens the phrase into a polite "would like to". Saying Vi vil vide sounds a bit demanding ("We want to know"), whereas Vi vil gerne vide is a much more natural and polite way to ask for information.
What is the dictionary form of tændte, and what is its opposite?