Three people are on a sidewalk.
Three friends are riding the bus.
People riding a bus are on the street, not on a sidewalk.
exists p1 x1.(exists x2.(on(x1,x2) & n_sidewalk(x2)) & n_people(x1) & card_eq_3(x1))
exists e1 x1 x2.(n_bus(x2) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_friend(x1) & card_eq_3(x1))