For one, your own bedroom is ta propre chambre, not ta chambre propre as explained in the comments below. For another, I don't think I've ever heard a francophone use "garder" to mean to guard. They would be more likely to use a word like protéger or defendre in a context like "guarding your bedroom."
Although I got it right, reading the comments made me realize that the meaning and placement of "clean" is interesting. In English, "You have to keep your clean room" has quite a different meaning than does "You have to keep your room clean" = but the construction in French seems to be the same. Now it is unlikely that your would give your "dirty" room away and keep the clean one, but the situation would be the same for "bleue". Any suggestions?
Yes, same construction in French but to avoid confusion you can say:
- You have to keep your clean room <-> Tu dois garder ta chambre propre., Tu dois garder ta chambre qui est propre.
- You have to keep your room clean <-> Tu dois garder ta chambre propre., Tu dois garder propre ta chambre.
- ma propre chambre = my own room
- ma chambre propre = my clean room.
In the sentence proposed here by Duo, in both languages a variation of word order can change the meaning, though not in the same way:
- I want to keep the room clean = je veux garder la chambre propre (so I clean it regularly)
- I want to keep the clean room = je veux garder la chambre propre (so I won't change this room for another one).
Perce, are you asking what are some ways to say this sentence in English? Here are some ways to say this sentence in English: You have to/need to/must keep your room clean/picked-up/neat/. You probably wouldn't say 'must' unless someone was refusing to keep their clean, then you could say to them 'You MUST keep your room clean.' (As in, if you don't keep your room clean there will be consequences.) 'Clean room' with the word 'clean' before the word 'room' is said in many sentences in english, but you would not say 'clean room' in this sentence unless there was a choice between keeping (conserver) your clean room or getting a new room that was dirty. Does that make sense and is that what you're asking?
'Propre' is one of those adjectives that changes meaning on placement, another that duolingo has covered both uses of is 'pauvre'. In both cases the literal meaning is conveyed when the adjective follows the noun (where adjectives normally go) whereas the metaphorical meaning is conveyed when the adjective is placed before the noun (like BANGS adjectives).
- chambre propre = clean bedroom
- enfant pauvre = child that is poor (lacking in financial resources)
- propre chambre = own bedroom
- pauvre enfant = poor child (child may be ill or in pain or upset)
This has been explained well elsewhere on this discussion page.