The girl is swimming is a blue-green ocean.
The girl is in the ocean.
The girl is in the ocean because you have to be in the ocean to swim in it.
exists p1 p2 x1 x2.(n_girl(x1) & exists s1 x4.((x1 = x4) & n_ocean(x4) & a_blue-green(s1) & Theme(s1,x4)) & exists x3.((x2 = x3) & n_swimming(x3)) & (x1 = x2))
exists p1 x1 x2.(n_ocean(x2) & n_girl(x1) & in(x1,x2))