A rock climber ascends.
Someone is hiking a trail.
although similar to hiking a climber has to climb up danger so you cannot be doing both.
exists e1 x1 x2.(Actor(e1,x1) & v_ascend(e1) & n_climber(x1) & of(x1,x2) & n_rock(x2))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_hike(e1) & n_trail(x2) & n_person(x1))