The boy in the red shirt is skateboarding.
A boy rides a skateboard.
One has to use a skateboard to do skateboarding.
exists e1 s1 x1 x2.(n_shirt(x2) & a_red(s1) & Theme(s1,x2) & n_boy(x1) & Actor(e1,x1) & v_skateboard(e1) & in(x1,x2))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_skateboard(x2) & n_boy(x1))