There's no way to know this is your hand/arm as opposed to my hand/arm. One could easily say this about oneself.
The solution needs to accept either "your hand/arm will..." or "my hand/arm will..." - at the moment it accepts neither.
No, this is alteration of translation. My hand will be sore = У меня будет болеть рука. Your hand will be sore = У тебя будет болеть рука. The correct translation The hand/arm will be sore. = Рука будет болеть.
Well, English prefers to be more specific. The Russian sentence essentially means that whoever is going to do the action in question (or take part in certain activity) is going to have their arm sore. In English one would likely say such a sentence using a generic "you" (your). Or, indeed, "I" (my) if the sentence is about yourself.
There's no context. Then you should translate the sentence from one language to the other. The only way you actually could elaborate your translation if you knew the context and could add my/your/his.
In Russian, the context would be clear. Doctor giving a shot, not to himself or to your mother. No need to disambiguate. "Ваша" does add formality, however.
Рука can be hand or arm in English. Without context we cannot know which. Why aren't both accepted here?
Yeah, I know. However, "(someone) will have a sore hand" might also work, but, being a non-native speaker I have no way to know that .:)
I also think that we (US) tend to use 'sore' to refer to pain specifically resulting from sports/exercise/repeated muscle use, so for this sentence "your hand/arm will be sore tomorrow" sounds totally correct to me, it just assumes something specific about the context.
For me (UK native speaker), "sore" is a very specific kind of pain. To say something will hurt is very general (the type of pain might be a sting, an ache, whatever). To say it will be sore suggests a particular kind of pain - probably with a sensation of heat, and there might be inflammation.
This is accepted now! I am very happy about this. Thank you, Duolingo staff <3
Взялось с перевода потому-что по-английски не говорим "hand" или "the hand". Определитель нужен - "your", "my", "his," и т.д.
I do not understand why they translate 'your hand' in place of 'hand'.