"Why don't you want to play baseball?"
Translation:¿Por qué no quieres jugar al béisbol?
Duo's answer suggested was '¿Por qué no quieres jugar al béisbol?' but isn't this sentence incorrect? I mean is 'al' in front of beisbol necessary? I wrote 'por que no quieres jugar el basebol' and got it wrong.
jugar + a + (el/la) + [sport] is the recommended^ form, and when it is a + el, it becomes al. (^in the official dictionary). jugar + [sport] is becoming more popular, and is permitted. However, it has to be one of these two forms. If you omit the a you must omit the word for the as well.
I don't understand why Duo is refusing "practicar béisbol".
Bruce, first let me say that I found several contradictions between sources for this so take this with a grain of salt... however:
For the most part my research shows that 'jugar' + 'a' is used for 'playing' sports like basketball, baseball, soccer, football, etc... This is in the context of just having fun playing the sport with friends.
Now if you were a member of a league or organized sports then you could use the verb 'practicar'. I think the implication is 'an ongoing practice' of playing the sport. I think you should report it as either could be inferred from the English sentence.
I don't think you can tell. I used the usted form and it was marked as incorrect.
Scott is correct. You cannot tell from the English which it is. You should report it as both versions (tu and usted) should be accepted. I'd also say 'ustedes' could also work here. Just make sure you conjugate the verb correctly.