A girls is jumping in the sand.
A girl is sitting in the sand.
Sitting and jumping are inherently different.
exists e1 x1 x2.(n_sand(x2) & in(e1,x2) & Actor(e1,x1) & v_jump(e1) & n_girl(x1))
exists e1 x1 x2.(n_sand(x2) & in(e1,x2) & Actor(e1,x1) & v_sit(e1) & n_girl(x1))