A man on a white bike doing tricks on rocky ground.
The man is skateboarding on rocky ground.
Someone on a bike cannot also be skateboarding at the same time.
exists e1 s1 s2 x1 x2 x3 x4 x5.(a_topic(x1) & on(x1,x2) & on(e1,x5) & n_ground(x5) & a_rocky(s2) & Theme(s2,x5) & Theme(e1,x4) & Actor(e1,x3) & v_do(e1) & n_trick(x4) & (x2 = x3) & n_bike(x2) & a_white(s1) & Theme(s1,x2) & n_man(x1))
exists e1 s1 x1 x2.(n_man(x1) & on(e1,x2) & n_ground(x2) & a_rocky(s1) & Theme(s1,x2) & Actor(e1,x1) & v_skateboard(e1))