I suppose the fact that he's doing his own homework is assumed. Therefore would "The children are doing their homework" be "Barnen sitter och gör läxan" and "I am doing my homework" be "Jag sitter och gör läxan?" Is there never a need to identify whose homework the subject is doing?
Yes, those are correct examples, except I would say "Barnen sitter och gör läxorna" unless they have a group homework. People have written about this before in another thread about body parts in Swedish, which I think is stickied somewhere. They explained it well there, so maybe try to find that. Anyway, like with body parts, things that are closely associated to a person generally are preferred to take the definite form rather than the possessive in Swedish. You can even refer to your girlfriend as "tjejen", your dad as "farsan" etc. Likewise if you are referring to your car, house, job. There are many examples where this applies. But it's not wrong and often doesn't sound strange to use the possessive (e.g. min, din), it's just less common.
We do this quite a lot. See the lesson notes here: https://www.duolingo.com/skill/sv/Continuous-Forms
I'm not completely sure that this works the same way for everyone, but when I click the icon to do a lesson, there's a lightbulb icon in the popup which leads to the lesson notes.
Another way is to add /tips-and-notes to the url manually. If, for instance, I start the lesson I have in front of me, it takes me to https://www.duolingo.com/skill/ru/Plurals/1
- ru = Russian
- Plurals = the skill I'm practising
- 1 = which lesson I'm at in the skill
I can replace the lesson number with "tips-and-notes" instead and it will show me the notes section - assuming the lesson has one; not all do. Like this:
We're teaching the construction with a position verb + och here. In English, the present continuous is doing means that he is doing it at the moment, while does would mean he habitually does his homework. Swedish of course doesn't distinguish between those two, so both can be gör läxan, but if we want to stress that we're talking about something that is happening right now, we use the construction with sitter och which expresses this, only stronger than the English sentence. (also see https://www.duolingo.com/skill/sv/Continuous-Forms)
I know this will have been discussed in other sentences of the same construction, but personally I can't see why Duo shouldn't accept "My son is sitting doing his homework." (no 'and'). It doesn't really mean a different thing to "he is doing his homework", except maybe there'd be a slight emphasis on the fact that he is nearby (you wouldn't use this construction for someone you just spoke to on the phone) AND an emphasis on the idea that he is doing it calmly and not causing any trouble for anyone. We are really not concerned with the fact that he is LITERALLY sitting (although, he would be, if we used this)... but to me, "he is sitting doing..." is a very natural construction and the one that most closely resembles the Swedish construction AND meaning. Happy to be shown otherwise though. Thanks.