A young girl wearing yellow flip-flops is sitting on a large boulder.
the girl is watching the sunset
The second sentence states that she is watching the sunset which is not clear in the first sentence which describes what she is wearing and where she is sitting.
exists e1 e2 s1 s2 s3 x1 x2 x3 x4.(on(e2,x4) & n_boulder(x4) & a_large(s3) & Theme(s3,x4) & Actor(e2,x1) & v_sit(e2) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_flip-flop(x3) & a_yellow(s2) & Theme(s2,x3) & (x1 = x2) & n_girl(x1) & a_young(s1) & Theme(s1,x1))
exists e1 x1 x2.(n_sunset(x2) & n_girl(x1) & Theme(e1,x2) & Actor(e1,x1) & v_watch(e1))