The large white bird's reflection shows in the water.
The large white bird is a pelican.
Not all white birds are pelican, it could be any number of other birds.
exists s1 s2 x1 x2 x3 x4.(n_water(x4) & n_show(x2) & of(x2,x3) & n_reflection(x3) & of(x2,x1) & n_bird(x1) & a_white(s2) & Theme(s2,x1) & a_large(s1) & Theme(s1,x1) & a_topic(x2) & in(x2,x4))
exists p1 s1 s2 x1.(n_bird(x1) & a_white(s2) & Theme(s2,x1) & a_large(s1) & Theme(s1,x1) & exists x2.((x1 = x2) & n_pelican(x2)))