A boy in a tank top skateboarding.
Girl is on a bike.
A boy skateboarding is not a girl on a bike.
exists s1 x1 x2 x3.(a_topic(x1) & in(x1,x2) & n_skateboarding(x2) & a_top(s1) & Theme(s1,x2) & of(x2,x3) & n_tank(x3) & n_boy(x1))
exists p1 x1.(ne_nam_girl(x1) & exists x2.(on(x1,x2) & n_bike(x2)))