They should really be accepting both answers. I know that sometimes it doesn't make that much sense but since there is no distinction between the way present simple and continuous are written, why not considered both answers right with a recommended one?
Would I ever say this sentence in Swedish when talking to someone? Are the rules for using definite and indefinite forms of words in Swedish the same as in English? Because sometimes I encounter examples that don't make much sense so I'm wondering... Thank you :D
The rules are roughly the same but there are some important cases where they differ. The idea of Duo is that you'll learn the language by being exposed to different examples, rather than teaching you single useful phrases.
That'd be a prime example of where it's actually used. :) Oh, you might find interesting that the male name Ulf has the same meaning. It's very common in Sweden, but you won't find that many people with that name under the age of, say, 45. :)