Two friends bike down a hill.
Boys are riding a bike.
Two friends is a form of boys.
exists x1 x2 x3.(a_topic(x1) & down(x1,x3) & n_hill(x3) & n_bike(x1) & of(x1,x2) & n_friend(x2) & card_eq_2(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_bike(x2) & n_boy(x1))