A group of people are rafting on river rapids.
Some people are rafting on their vacation.
Rafting is an activity that stands alone without vacation.
exists e1 x1 x2 x3 x4.(on(e1,x3) & n_rapid(x3) & of(x3,x4) & n_river(x4) & Actor(e1,x1) & v_raft(e1) & of(x1,x2) & n_people(x2) & n_group(x1))
exists e1 x1 x2.(on(e1,x2) & n_vacation(x2) & of(x2,x1) & n_thing(x1) & Actor(e1,x1) & v_raft(e1) & n_people(x1))