Emma proved that a citizen offered a frog a cake on the stage .
* stage ( x _ 12 ) ; prove . agent ( x _ 1 , Emma ) AND prove . ccomp ( x _ 1 , x _ 5 ) AND citizen ( x _ 4 ) AND offer . agent ( x _ 5 , x _ 4 ) AND offer . recipient ( x _ 5 , x _ 7 ) AND offer . theme ( x _ 5 , x _ 9 ) AND frog ( x _ 7 ) AND cake ( x _ 9 ) AND cake . nmod . on ( x _ 9 , x _ 12 )