How do you recognise when "uma" means "a" and when it means "one"?
There is no such distinction in Portuguese; probably intonation and context will give you a better idea of whether you're talking about an onion in indeterminate terms or one single onion (vs. two onions, three carrots and seven potatoes).
The sound of this onion(cebola) is wrong
It is 'cebola', in Portuguese, this is not in Spanish which is 'cebolla'. DuoLingo is right this time!
Eu sei que é em português, eu sou Brasileiro.
I know it is in Portuguese, I'm Brazilian.
me too . im full blood brazilian