two boys on a balance beam holding a rope
Boys going through rapids in canoe.
Boys can be more than two boys.  If boys are on a balance beam they are not going through rapids in a canoe.
exists e1 x1 x2 x3 x4 x5.(a_topic(x1) & on(x1,x2) & Theme(e1,x5) & Actor(e1,x4) & v_hold(e1) & n_rope(x5) & (x2 = x4) & n_beam(x2) & of(x2,x3) & n_balance(x3) & n_boy(x1) & card_eq_2(x1))
exists e1 x1 x2 x3 x4.(a_topic(x1) & in(e1,x4) & n_canoe(x4) & through(e1,x3) & n_rapid(x3) & Actor(e1,x2) & v_go(e1) & (x1 = x2) & n_boy(x1))