Skateboarder grinds a concrete railing.
The person is doing a kick flip
a grind and a kick flip are 2 different things
exists e1 s1 x1 x2.(ne_nam_skateboarder(x1) & Theme(e1,x2) & Actor(e1,x1) & v_grind(e1) & n_railing(x2) & a_concrete(s1) & Theme(s1,x2))
exists e1 x1 x2 x3.(n_person(x1) & Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_flip(x2) & of(x2,x3) & n_kick(x3))