A man and a woman are sleeping while sitting in a bus or train of some kind.
A married couple sleeping on an overnight trip to visit friends.
man and a woman  doesn't imply married couple
exists e1 e2 x1 x2 x3 x4 x5.(while(e1,e2) & in(e2,x4) & of(x4,x5) & n_kind(x5) & (n_bus(x4) | n_train(x4)) & Actor(e2,x1) & v_sit(e2) & Actor(e1,x1) & v_sleep(e1) & subset_of(x3,x1) & n_woman(x3) & subset_of(x2,x1) & n_man(x2))
exists e1 p1 s1 s2 x1 x2 x3.(a_topic(x1) & on(e1,x3) & Topic(x3,p1) & exists e2 x4.(Theme(e2,x4) & Actor(e2,x3) & v_visit(e2) & n_friend(x4)) & n_trip(x3) & a_overnight(s2) & Theme(s2,x3) & Actor(e1,x2) & v_sleep(e1) & (x1 = x2) & n_couple(x1) & a_married(s1) & Theme(s1,x1))