A man is grilling kebabs on a barbecue.
A man is standing by a grill.
man is grilling kebabs simply means man is standing by a grill
exists e1 x1 x2 x3.(on(e1,x3) & n_barbecue(x3) & Theme(e1,x2) & Actor(e1,x1) & v_grill(e1) & n_kebab(x2) & n_man(x1))
exists e1 x1 x2.(by(e1,x2) & n_grill(x2) & Actor(e1,x1) & v_stand(e1) & n_man(x1))