People are sitting on a snowy mountain.
Snowboarders are resting in the snow on the mountainside.
Snowboarders are not the only type of people that may be in the snow. Resting is not the only reason for sitting on a mountainside.
exists e1 s1 x1 x2.(on(e1,x2) & n_mountain(x2) & a_snowy(s1) & Theme(s1,x2) & Actor(e1,x1) & v_sit(e1) & n_people(x1))
exists e1 x1 x2 x3.(n_mountainside(x3) & n_snow(x2) & in(e1,x2) & on(x2,x3) & Actor(e1,x1) & v_rest(e1) & n_snowboarder(x1))