I used to get very frustrated with Doulingo when it did that to me, then, I realized that people do reverse trees to improve the other language they are learning. For instance, I'm here as an English speaker learning Spanish, however, when I finished the Spanish tree, I went to the English for Spanish speakers course (the clarification is rather for those who don't know what a reverse tree is). Now, imagine if they accepted my spelling mistakes in Spanish, my recently learnt language would be totally messed up!
I put 'commandant' which means "the commanding officer in charge of a particular military organization" -- the equivalent of commander - because the nature of the Spanish word put commandant into my mind, though I haven't heard it used since my days as a military kid. But Duolingo won't accept it.
I believe you would need to capitalize it as part of a proper title and include the remainder of the title unless context has been established. Also the context you implied is a higher rank than that of commander 'proper', an O-5 in the USN, and separate again in context.
Yeah, but, shouldn't you specify the particular military unit for the sake of commplete accuracy? Why submit a shody translation when you can so easily keep going and fill it out? Why leave such huge lose ends? Yet, still, apart from that detail, seemed perfectly accurate to me and Duo should accept it in consideration of your service record. Obviously.
In spanish you use "un" for male things and "una" for female ones. ---- Un perro -- Una manazana
It's the same when you need plurals: "unos" for male and "unas" for females. ---Unos perros--Unas manzanas
The same with THE: For singular: "el" male and "la" female"--- El perro--La manzana For plural: "los" male and "las" female"---Los perros--Las manzanas