A man and woman kiss on a train.
A couple kissing on a crowded train.
A man and a woman does not make a train crowded.
exists s1 x1 x2 x3 x4.(a_topic(s1) & subset_of(x2,s1) & on(x2,x4) & n_train(x4) & n_kiss(x2) & of(x2,x3) & n_woman(x3) & subset_of(x1,s1) & n_man(x1))
exists e1 s1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_train(x3) & a_crowded(s1) & Theme(s1,x3) & Actor(e1,x2) & v_kiss(e1) & (x1 = x2) & n_couple(x1))