A bulldozer is working on a building.
There is a yellow bulldozer.
Not all bulldozers are yellow.
exists e1 x1 x2.(on(e1,x2) & n_building(x2) & Actor(e1,x1) & v_work(e1) & n_bulldozer(x1))
exists p1 x1 s1 x2.((x1 = x2) & n_bulldozer(x2) & a_yellow(s1) & Theme(s1,x2))