It's an incredibly slight difference between the two. djur has more of a 'u' sound and the o(I dont have the keyboard set to Swedish on this computer) in gor is a more open sound. The u is more of a closed mouth whereas your mouth is open to say o. The u sound in djur sounds like the o in two. The o sound in gor is the oo in good as far as the position of the mouth, not necessarily the exact sound.
I'd say that "under" is at some point during, and "över" is until it ends.
Jag har lånat en bok över helgen - I have borrowed a book over the weekend (probably got it friday and will return it monday morning, or at least early sat. to late sunday)
Jag ska läsa en bok under helgen - I'll read a book during the weekend (Not the whole time, but at some point)
It is not always any real difference though.
Is "helg" really the same as "weekend" in Swedish? I spent 11 years in Sweden, studied in Uppsala etc., but for me the Swedish word for "weekend" always was "weekend". "Helg" in my humble opinion (though I'm not a native speaker, that's true) is a "holy day", every sort of it. Am I really so largely mistaken?
I remember even the term "veckoslut" for weekend. But the weekend doesn't seem so holy to me to merit the name of the "helg". Am I mistaken?
It can be easy to miss this kind of thing. We can say weekend in Swedish for instance if we book en weekendresa 'a weekend trip'. But in most cases, the weekend is helgen and 'a holy day' is rather en helgdag. Words like veckoslut and veckända are used by some speakers, it can be both regional (saying veckoslut is common in Finland) and possibly a question of sociolect or age, but helg is the overwhelmingly most common and neutral word.
I am not a native speaker (neither swedish nor english) and I always thought it must be "will" (what will you do...). I even asked some brittish people who told me that "what do you do at the weekend" sounds very German. (We germans say "was machst du" for presend and most times for future. We have the "werden"-future but we dont use it) So can native english speakers tell me whether "will do" and "are doing" are equally acepted? Thanks!