An climber is ascending an ice covered rock face.
A person is sitting on a couch.
A person cannot be described as a climber if sitting.  The person is either sitting or climbing.
exists e2 e1 x1 x2 x3 x4 x5.(Theme(e2,x2) & Actor(e2,x1) & v_ascend(e2) & Time(e1,x5) & n_rock(x5) & Time(e1,x4) & n_face(x4) & Theme(e1,x3) & v_cover(e1) & (x2 = x3) & n_ice(x2) & n_climber(x1))
exists e1 x1 x2.(on(e1,x2) & n_couch(x2) & Actor(e1,x1) & v_sit(e1) & n_person(x1))