A guy in a white shirt skateboarding on a ramp.
A skateboarder rolls along.
To skateboard, you must roll along the ground with the skateboard. Also, a guy in a white shirt skateboarding implies he is a skateboarder.
exists e1 s1 x1 x2 x3 x4.(a_topic(x1) & in(x1,x2) & on(e1,x4) & n_ramp(x4) & Actor(e1,x3) & v_skateboard(e1) & (x2 = x3) & n_shirt(x2) & a_white(s1) & Theme(s1,x2) & n_guy(x1))
exists e1 p1 x1.(exists s1.(Theme(s1,x1) & a_along(s1)) & Topic(e1,p1) & Actor(e1,x1) & v_roll(e1) & n_skateboarder(x1))