The wheel of the bus is being held by a person in a black shirt.
a good Samaritan changes a flat tire on a bus
A person in a black shirt doesn't imply that they are a good Samaritan.
exists e1 s1 x1 x2 x3 x4.(n_bus(x2) & n_wheel(x1) & Actor(e1,x3) & in(x3,x4) & n_shirt(x4) & a_black(s1) & Theme(s1,x4) & n_person(x3) & Theme(e1,x1) & v_hold(e1) & of(x1,x2))
all s1 x1.((n_tire(x1) & a_flat(s1) & Theme(s1,x1)) -> exists s2 x2 x3 x4.(a_topic(x2) & on(x2,x4) & n_bus(x4) & for(x2,x1) & n_change(x2) & of(x2,x3) & n_samaritan(x3) & a_good(s2) & Theme(s2,x2)))