One mechanic is sitting on the roof of a school bus with an open door, while the other is standing inside the bus.
A mechanic is standing of the roof of a truck, another mechanics is in the cab of the truck.
He can either be sitting or standing, but not both.
exists e1 p1 s1 x1 x2 x3 x4 x5 x6.(n_other(x6) & n_roof(x2) & exists e2.(inside(e2,x3) & Actor(e2,x6) & v_stand(e2)) & n_bus(x3) & n_bus(x3) & while(e1,p1) & with(e1,x5) & n_door(x5) & a_open(s1) & Theme(s1,x5) & on(e1,x2) & of(x2,x3) & of(x3,x4) & n_school(x4) & Actor(e1,x1) & v_sit(e1) & n_mechanic(x1) & card_eq_1(x1))
exists e1 p1 x1 x2 x3 x5.(n_cab(x5) & n_roof(x2) & of(e1,x2) & of(x2,x3) & exists p2 x4.(in(x4,x5) & of(x5,x3) & n_mechanic(x4) & -(x4 = x1)) & n_truck(x3) & n_truck(x3) & n_mechanic(x1) & n_mechanic(x1) & that(x3,p1) & Actor(e1,x1) & v_stand(e1))