Two people on a sled pulled by a team of dogs.
Two people are dog sledding.
People on a sled pulled by dogs means they are dog sledding.
exists e1 x1 x2 x3 x4 x5.(a_topic(x1) & on(x1,x2) & Actor(e1,x4) & of(x4,x5) & n_dog(x5) & n_team(x4) & Theme(e1,x3) & v_pull(e1) & (x2 = x3) & n_sled(x2) & n_people(x1) & card_eq_2(x1))
exists p1 x1.(exists x2 x3.((x1 = x2) & n_sledding(x2) & of(x2,x3) & n_dog(x3)) & n_people(x1) & card_eq_2(x1))