"My uncle spends all his time on playing ninja."
Translation:Min onkel bruger al sin tid på at lege ninja.
I’m obviously too ignorant for these tests. I don’t know what playing ninja is. Does it mean dressing up and acting like a ninja or does it mean playing a game called ninja. Either way, “spille” should be accepted as well as “lege”. It is not. From the comments I see that other people’s comments saying the same or asking about the use of “spil” have disappeared into that great Duolingo vacuum from which no response ever appears.