A skier speeds through the snow.
A hiker rests at a lodge.
The person cannot simultaneously be a skier and a hiker
exists e1 x1 x2.(n_snow(x2) & through(e1,x2) & Actor(e1,x1) & v_speed(e1) & n_skier(x1))
exists e1 x1 x2.(at(e1,x2) & n_lodge(x2) & Actor(e1,x1) & v_rest(e1) & n_hiker(x1))