A shoe shiner waits for customers.
A person shining shoes.
If the person is waiting for customers, he cannot currently be shining shoes.
exists x1 x2 x3 x4.(a_topic(x1) & for(x1,x4) & n_customer(x4) & n_wait(x1) & of(x1,x3) & n_shiner(x3) & of(x1,x2) & n_shoe(x2))
exists e1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_shine(e1) & n_shoe(x3) & (x1 = x2) & n_person(x1))