"Whose fly is it?"
Translation:Чья это муха?
> It's not an 'eto' revealing information, right?
It is. This course assumes you choose the closest variant, so:
- Чья э́то му́ха? = Whose fly is it?
- Чья э́та му́ха? = Whose is this fly?
Thanks! I was thinking along the lines of 'чей, чья, чьё, чьи' = 'to whom belongs' and thought a demonstrative adjective must follow to agree with noun. Found my clarification: http://www.russianforeveryone.com/Rufe/Lessons/Course1/Grammar/GramUnit3/GramUnit3_2.htm
that depends on the grammatical gender like my/your/our https://www.duolingo.com/skill/ru/Possessive-Modifiers-1/tips-and-notes sometimes you must just remember it - like we russians have to remember that in English ship is "she" and fox is "he" But you at last can consult the dictionary! *-)
The answer would be in nominative («Му́ха моя́.» ‘The fly is mine’) or genitive («Му́ха Андре́я» ‘The fly is Andrew’s’).