A rollerblader on a concrete form.
the rollerblader is performing for a crowd
Being on a concrete form does not mean the rollerblader is performing.
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_rollerblader(x1) & for(e1,x2) & n_crowd(x2) & Actor(e1,x1) & v_perform(e1))