A boy is surrounded by pigeons.
The boy is near birds.
Pigeons are a type of bird.
exists e1 x1 x2.(Actor(e1,x2) & n_pigeon(x2) & Theme(e1,x1) & v_surround(e1) & n_boy(x1))
exists p1 x1.(n_boy(x1) & exists s1 x2.((x1 = x2) & n_bird(x2) & a_near(s1) & Theme(s1,x2)))