Guys are running in a marathon.
Guys and girls are running.
We don't know why they are running.
exists e1 x1 x2.(in(e1,x2) & n_marathon(x2) & Actor(e1,x1) & v_run(e1) & n_guy(x1))
exists e1 x1 x2 x3.(Actor(e1,x1) & v_run(e1) & subset_of(x3,x1) & n_girl(x3) & subset_of(x2,x1) & n_guy(x2))