A man and a woman greeting each other on bikes in front of a building.
A couple meets for a ride.
A man and woman greeting each other are not assumed to be a couple who meets.  Being on bikes does not necessarily imply that they are going to go for a ride.
exists s1 x1 x2 x3.(a_topic(s1) & subset_of(x2,s1) & all x4.(n_other(x4) -> exists e1 x5 x6 x7.(in(e1,x6) & of(x6,x7) & n_building(x7) & n_front(x6) & on(e1,x5) & n_bike(x5) & Theme(e1,x4) & Actor(e1,x3) & v_greet(e1))) & (x2 = x3) & n_woman(x2) & subset_of(x1,s1) & n_man(x1))
exists e1 x1 x2.(for(e1,x2) & n_ride(x2) & Actor(e1,x1) & v_meet(e1) & n_couple(x1))