Four ferry boats are docked at a visitor's center with passengers waiting to board.
The people are needed to go somewhere.
People who need to go somewhere don't necessarily have ferries waiting for them.
exists e2 e1 x1 x2 x3 x4 x5 x6 x7.(at(e1,x4) & with(x4,x5) & to(e2,x7) & n_board(x7) & Actor(e2,x6) & v_wait(e2) & (x5 = x6) & n_passenger(x5) & n_center(x4) & of(x4,x3) & n_visitor(x3) & Theme(e1,x1) & v_dock(e1) & n_boat(x1) & of(x1,x2) & n_ferry(x2) & card_eq_4(x1))
exists e1 p1 x1.(n_people(x1) & Recipient(e1,p1) & Topic(e1,x1) & v_need(e1) & exists e2 x2.(Location(e2,x2) & n_location(x2) & Actor(e2,x1) & v_go(e2)))