A skateboarder uses a ramp.
A man is doing an impressive skateboard trick.
All skateboarders aren't men and using a ramp doesn't mean the skateboarder is doing a skateboard trick.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_use(e1) & n_ramp(x2) & n_skateboarder(x1))
exists e1 s1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_trick(x2) & of(x2,x3) & n_skateboard(x3) & a_impressive(s1) & Theme(s1,x2) & n_man(x1))