A person riding a snowboard goes over a snowy ramp.
A group of skiers speeding down the hill.
People cannot be skiers and ride a snowboard at same time.
exists e1 e2 s1 x1 x2 x3 x4.(over(e2,x4) & n_ramp(x4) & a_snowy(s1) & Theme(s1,x4) & Actor(e2,x1) & v_go(e2) & Theme(e1,x3) & Actor(e1,x2) & v_ride(e1) & n_snowboard(x3) & (x1 = x2) & n_person(x1))
exists e1 x1 x2 x3 x4.(n_hill(x4) & a_topic(x1) & down(e1,x4) & Actor(e1,x3) & v_speed(e1) & (x1 = x3) & of(x1,x2) & n_skier(x2) & n_group(x1))