A woman and boy sit on a police motorcycle.
A woman and boy are outside.
A motorcycle may be indoors like in a garage and doesn't have to be outside.
exists e1 x1 x2 x3 x4 x5.(on(e1,x4) & n_motorcycle(x4) & of(x4,x5) & n_police(x5) & Actor(e1,x1) & v_sit(e1) & n_boy(x3) & n_woman(x2) & subset_of(x3,x1) & subset_of(x2,x1))
exists s1 x1 x2 x3.(Theme(s1,x1) & a_outside(s1) & n_boy(x3) & n_woman(x2) & subset_of(x3,x1) & subset_of(x2,x1))