"The cat is drinking milk."
Translation:Kedi süt içiyor.
How come 'Kedi sütü içiyor' is wrong, when 'milk' is the object of the sentence? Is it because milk is an uncountable entity?
No. Kedi sütü içiyor is a correct sentence. But it's the translation of the cat is drinking THE milk (that you put in front of it.), so it's some specific milk we're talking about.
Now imagine you see a random stray cat that is drinking some milk. You don't know the backstory. In that case, you would say kedi süt içiyor. - the cat is drinking milk. Some milk.