A medium sized animal in a lake
A medium-sized animal is in a lake.
Is in a lake is a rephrasing of in a lake.
exists e1 x1 x2 x3.(a_topic(x1) & in(x1,x3) & n_lake(x3) & n_animal(x1) & Theme(e1,x1) & v_size(e1) & of(x1,x2) & n_medium(x2))
exists p1 s1 x1.(exists x2.(in(x1,x2) & n_lake(x2)) & n_animal(x1) & a_medium-sized(s1) & Theme(s1,x1))