Translation:I am standing
Duolingo is asking that I write the English for an English sentence. Clearly, there is a programming error here.
Yeah, seems like a glitch that only you got, because your comment has appeared on the exercise: Ninasimama > I am standing. And yeah, I'm quite positive that ninasimama is not English.
"I stop" is probably correct also. This meaning would be applied in some contexts but not others I think.