Translation:They had not been at home, so the newspapers were still lying outside their door.
"they lay outside the door" Does Norwegian have the subjunctive case by the way??
"... the newspapers still lay outside their door."
There is a subjunctive case in archaic expressions, but that's about it. The Norwegian Bible, however, is written rather conservatively, and still has many such expressions, but it would be regarded as an exception. I'm not aware of any other texts which make use of the case.
"(Lenge) leve kongen!" = "Long live the king!"
It's pretty much non-existent in modern Norwegian, and most Norwegians won't even know it exists/existed.
Why is it "døra?" That seems like it would be "the doors," not "the door." I am only guessing because "barnet" is "the child" whereas "barna" is "the children."
The endings depend on the gender. -a is the definite singular ending for feminine nouns, but the definite plural ending for neuter nouns.