A rollerblader on a concrete form.
a person is rollerblading on the concrete
A rollerblader is a person, and concrete is a concrete form.
exists s1 x1 x2.(a_topic(x1) & on(x1,x2) & n_form(x2) & a_concrete(s1) & Theme(s1,x2) & n_rollerblader(x1))
exists e1 x1 x2.(n_concrete(x2) & on(e1,x2) & Actor(e1,x1) & v_rollerblade(e1) & n_person(x1))