A small boy swimming underwater
The boy was a good diver.
A boy who is a good diver means he can swim well underwater.
exists s1 x1 x2 x3.(a_topic(x1) & n_underwater(x1) & of(x1,x3) & n_swimming(x3) & of(x1,x2) & n_boy(x2) & a_small(s1) & Theme(s1,x1))
exists p1 x1.(n_boy(x1) & exists s1 x2.((x1 = x2) & n_diver(x2) & a_good(s1) & Theme(s1,x2)))