"Am bi thu a' cluiche ball-basgaid a-nochd?"
Translation:Will you be playing basketball tonight?
I agree that the response "are you playing basketball tonight?" is a more accurate expression of the meaning of this sentence in english. No one would say "Will you play basketball tonight". Its awkward and too formal. It is like translating "Bidh Màiri a' cluiche iomain uaireannan" as "Mairi will sometimes play shinty" instead of "Mairi plays shinty sometimes".
I have been marked wrong on this and it appears that this is another example of the hypenated version "ball-basgaid" comes out as wrong but the non-hyphenated "ball" "basgaid" as correct. I know that DL have an issue with these glitches and hope they are fixed as soon as they are able to do so.