A young girl floats on her back in water and peers over her life jacket.
A girl floats in the water with a life jacket.
A young girl is a type of girl.  Since she peers over her life one can assume that she has the life jacket on and is therefore in the water with a life jacket.
exists s1 x1 x2 x3 x4 x5 x6 x7 x8.(a_topic(x1) & on(x1,x3) & subset_of(x6,x3) & over(x6,x7) & n_jacket(x7) & of(x7,x8) & n_life(x8) & of(x7,x1) & n_female(x1) & n_female(x1) & n_peer(x6) & subset_of(x4,x3) & in(x4,x5) & n_water(x5) & n_back(x4) & of(x4,x1) & n_float(x1) & of(x1,x2) & n_girl(x2) & a_young(s1) & Theme(s1,x1))
exists e1 x1 x2 x3 x4.(n_water(x2) & in(e1,x2) & with(x2,x3) & n_jacket(x3) & of(x3,x4) & n_life(x4) & Actor(e1,x1) & v_float(e1) & n_girl(x1))