Ah, in that sense. I did notice that "grand" was not allowed for "granda" in another example, when I tried it. Not sure about "great". They all seem more or less synonymous to me—with some nuance differences, but still—so I would say it's probably more or less correct as an equivalent or as a translation (if not on this course, at least for the moment). Don't pin me down on that, though, I'm new at Esperanto.