"I am drinking the water."
Translation:Jeg drikker vannet.
Can someone please explain (without simply saying 'it's a noun' etc - I simply don't understand that, because Duolingo doesn't teach grammar so such comments are unfortunately lost on me) why here 'the water' is vannet, whilst in other random situations it has been vannen. Is there a specific thing I have to watch for, or do I just have to learn as I go and hope for the best? Thank you :)
It has never been 'vannen'. The noun endings are explained in the Tips and Notes section in this skill. This should be available if you access Duolingo by PC, but I've heard the Apps for phones have been lacking this feature. I'd recommend you to read it on a PC if you get the opportunity.
To answer your question: Every noun has a grammatical gender in Norwegian; feminine, masculine and neuter. These are usually not related to the actual gender of the noun, but every noun is either one of these, and has its own rules inflection. The exception here is the feminine nouns, which can always be inflected as masculine(but not the other way around). The gender of a noun has to be memorized as there are no clear rules for this.
In the the case of 'vann', this is a neuter noun, so the definite form is always 'vannet'. A masculine noun would end in -en, but 'vann' isn't a masculine noun. 'hund' would be an example of a masculine noun: 'hunden', while 'katt' is a feminine noun, so either 'katta' or 'katten'.
On a related note: 'vann' has two meanings in Norwegian, either 'water' or 'lake'. 'water' is an uncountable noun, and only exist in two forms: indefinite and definite singular, while 'lakes' has all four forms:
water - the water = vann - vannet
a lake - the lake - lakes - the lakes = et vann, vannet, vann, vannene