We have these 2x meanings in English also.
"I must clean in my room" has a different meaning from "I must clean my room".
The first is more general, its meaning exactly is "I must be engaged in the process of cleaning, while in my room" and could mean 1) cleaning the room, or 2) clean a bit of the room, or even 3) clean something else in the room (as James points out above).
The second very specifically states only meaning #1
What the hell... Why in one sentence "muszę" is "I must", and in another is "I should"? How should I distinguish?
Previous task was "muszę pomóc mamie" or suchlike, and "I must" wasn't accepted, but there was stated that "I should" is ok. And it is always accepts "I need". Brain exploding word)))
Thanks, that makes sense :)
Although perfective/imperfective verb forms will cause me trouble for some time yet...
Related: Why did Duo offer us just sprzątać in various earlier exercises, e.g.
W soboty sprzątam mój pokój (On Saturdays I tidy my room)
Ona pomogła nam sprzątać dom (She helped us clean/tidy the house).
Mama zaczęła sprzątać pokój. (Mum has started to clean/tidy the room) - presumably OK because she hasn't finished yet.
I do agree with JamesTWils.
Well, the first one is for sure imperfective, because it's in Present Simple, and it's impossible to use perfective in the Present Tense.
The second one indeed could be both, as written by James.
The third one has to be imperfective because she indeed hasn't finished yet. Not in this sentence, anyway ;)
Perfective/imperfective is tough. Imperfective does not just mean that the action is unfinished, though, but rather emphasizes the action itself, rather than the goal. So in the first bullet point there, you are emphasizing the work that you do over a period of time every Sunday, rather than the completed orderly room. The last bullet point, as you note, is ongoing work. The second bullet point, I think (though I'd be happy to be corrected by a Pole), could be either imperfective or perfective. The imperfective here emphasizes the work, the actual drudgery, that she is helping us with. The perfective would emphasize the project of cleaning that she had helped us complete.
So, if I got it right: if I say "muszę sprzątać moim pokoju" it means that I must clean even if I get no results from my actions (reality hurts!) ; and if I say "muszę posprzątać..." it means I must leave it clean in the end (or else!...) That's what perfective verbs means? I still don't get the verbs' logic, it seems as if instead of conjugating one verb, we have to change verbs to explain things like the time, etc.
I don't know if it was just a typo, but you missed "w" ("w moim pokoju").
I guess "muszę sprzątać" is something you could say to your friend explaining why you cannot meet them right now (you're too busy cleaning, probably someone told you to do that), but the end result isn't exactly that important - the important part is that you're too busy. So yeah, even if there will be no results.
"muszę posprzątać" - at the end, the room has to be clean. So yeah, your comment sounds right.