Questions & Answers about Dekorasjonen er ferdig.
Because dekorasjonen is the definite singular form, meaning the decoration.
- en dekorasjon = a decoration
- dekorasjonen = the decoration
In Norwegian, definiteness is usually added to the end of the noun as a suffix:
- en bil = a car
- bilen = the car
So Dekorasjonen er ferdig literally matches The decoration is finished/ready.
The base form is dekorasjon.
This is a noun, and its common forms are:
- en dekorasjon = a decoration
- dekorasjonen = the decoration
- dekorasjoner = decorations
- dekorasjonene = the decorations
So in the sentence, you are seeing the noun in its definite singular form.