a boy smiles underwater.
a boy is swimming beneath the surface and enjoying himself.
Since  boy is swimming underwater, he is  enjoying  and smiles
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_smile(e1) & n_underwater(x2) & n_boy(x1))
exists e2 e1 x1 x2 x3.(n_male(x2) & n_surface(x2) & Theme(e2,x2) & Actor(e2,x3) & v_enjoy(e2) & n_boy(x3) & beneath(e1,x2) & Actor(e1,x1) & v_swim(e1) & n_boy(x1))