Breakdown of I onsdags underviste hun på konferencen.
hun
she
i
in
på
on / at / in (a language) / of (after nouns like end or start)
onsdag
Wednesday
Questions & Answers about I onsdags underviste hun på konferencen.
Why does onsdags have an -s at the end here?
Adding an -s to a weekday and putting i in front of it is how Danish says 'last [weekday]'. So i onsdags means 'last Wednesday'. If you were talking about an upcoming Wednesday, you would use på and leave off the -s, making it på onsdag.
Why are the subject and verb swapped here (underviste hun instead of hun underviste)?
This is the Danish V2 rule in action. The verb must be the second piece of information in the sentence. Since the time phrase I onsdags takes the first spot, the verb underviste has to come next, pushing the subject hun into the third spot.
Why use på for 'at the conference' instead of another preposition?
The preposition på is commonly used in Danish for attending events, institutions, and workplaces. Just like you say på arbejde (at work) or på hospitalet (at the hospital), you say på konferencen for being at a conference.
What is the base form of the verb underviste?
The base form (infinitive) is at undervise, which means 'to teach'. The word underviste is the past tense, so it translates to 'taught'.