A helicopter is flying behind a plane that is performing aerobatics.
Two vehicles flying.
Two vehicles here refers to a helicopter is flying behind a plane
exists e2 e1 x1 x2 x3 x4.(behind(e1,x2) & Theme(e2,x4) & Actor(e2,x3) & v_perform(e2) & n_aerobatics(x4) & (x2 = x3) & n_plane(x2) & Actor(e1,x1) & v_fly(e1) & n_helicopter(x1))
exists e1 x1.(Actor(e1,x1) & v_fly(e1) & n_vehicle(x1) & card_eq_2(x1))