A young man does a trick on his skateboard on a slope.
A person is skateboarding.
A person doing trick with a skateboard on a slope he should be well trained!!!
exists e1 s1 x1 x2 x3 x4.(on(e1,x4) & n_slope(x4) & on(e1,x3) & n_skateboard(x3) & of(x3,x1) & n_male(x1) & Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_trick(x2) & n_man(x1) & a_young(s1) & Theme(s1,x1))
exists e1 x1.(Actor(e1,x1) & v_skateboard(e1) & n_person(x1))