Two children are climbing stairs which lead to an airplane.
Two children board an airplane.
The children who are climbing stairs to enter an airplane are boarding an airplane.
exists e2 e1 x1 x2 x3 x4.(Theme(e2,x2) & Actor(e2,x1) & v_climb(e2) & to(e1,x4) & n_airplane(x4) & Actor(e1,x3) & v_lead(e1) & (x2 = x3) & n_stair(x2) & n_child(x1) & card_eq_2(x1))
all x1.(n_airplane(x1) -> exists x2 x3.(a_topic(x2) & for(x2,x1) & n_board(x2) & of(x2,x3) & n_child(x3) & card_eq_2(x2)))