A girl in a life jacket is swimming while others watch from the rocks.
A girl swimming alone.
If everyone else is on the rocks then it is imolied the girl is alone.
exists e1 p1 x1 x2 x3 x5.(n_rock(x5) & exists e2 x4.(from(e2,x5) & Actor(e2,x4) & v_watch(e2) & -(x4 = x1) & n_person(x4)) & n_person(x1) & while(e1,p1) & Actor(e1,x1) & v_swim(e1) & in(x1,x2) & n_jacket(x2) & of(x2,x3) & n_life(x3) & n_girl(x1))
exists x1 x2.(a_topic(x1) & r_alone(x1) & n_swimming(x1) & of(x1,x2) & n_girl(x2))