"She works in a factory."

Translation: Hon arbetar på en fabrik.

[Boddason]

Why "på en fabrik" and not "på fabrik"? Or is just something you've go to learn?

[Arnauti]

Actually på fabrik works too, I'll add it as an accepted answer. It's hard to explain when the article can be left out, but generally when the verb + object are seen as a kind of unit. So in a way yes, one has got to learn in which cases it's like that.

[Boddason]

Vielen Dank!
(Entschuldigung, fast hätte ich vergessen Danke! zu sagen.)
(Vad heter det på svenska? Jag är tysk...)

[Arnauti]

Tack så mycket! Förlåt, jag glömde nästan att säga tack!

[sim-hae]

Can't she work "i en fabrik" also? :)

[Lundgren8]

Yes, that also works in this particular context.

[bonbonaj3]

Would "på" or "i" be more common?

[creativemetaphor]

But it is marked incorrect.

[Lundgren8]

”Jobbar i en fabrik” was marked correct, but not ”arbetar”, it’s fixed now. Thanks.

[creativemetaphor]

:)