A girl is sitting on a guy's lap at a party.
A guy and a girl are at a party, sitting together.
"A guy and a girl are sitting together" is a rephrasing of " a girl is sitting on a guy's lap".
exists e1 x1 x2 x3 x4.(at(e1,x4) & n_party(x4) & on(e1,x3) & n_lap(x3) & of(x3,x2) & n_guy(x2) & Actor(e1,x1) & v_sit(e1) & n_girl(x1))
exists e1 p1 s1 x1 x2 x3.(for(p1,e1) & a_together(s1) & Manner(e1,s1) & Actor(e1,x1) & v_sit(e1) & exists x4.(at(x1,x4) & n_party(x4)) & subset_of(x3,x1) & n_girl(x3) & subset_of(x2,x1) & n_guy(x2))