The solution wants us to write:"A young man, a white dog, a strange professor and an angry Frenchman are on the Moon," but there is a lot of choices missing.
And the two hopeless policemen, no? I don't remember the story that well :)
Why not "Kuussa... " and so on as in other examples?
is the "in" suffix (-ssa) also used to mean "on" or is that just a context change?