Two children run towards the lagoon.
Two children walk at a lagoon.
If the children walk at a lagoon they have already arrived and cannot run towards the lagoon.
exists e1 x1 x2.(n_lagoon(x2) & towards(e1,x2) & Actor(e1,x1) & v_run(e1) & n_child(x1) & card_eq_2(x1))
exists e1 x1 x2.(at(e1,x2) & n_lagoon(x2) & Theme(e1,x1) & v_walk(e1) & n_child(x1) & card_eq_2(x1))