There is a little boy sitting in a chair.
The little boy is sitting in a rocking chair.
The boy could be sitting in any kind of chair, not necessarily a rocking chair.
exists p1 x1 e1 s1 x2 x3 x4.((x1 = x2) & in(e1,x4) & n_chair(x4) & Actor(e1,x3) & v_sit(e1) & (x2 = x3) & n_boy(x2) & a_little(s1) & Theme(s1,x2))
exists e1 s1 x1 x2 x3.(n_boy(x1) & a_little(s1) & Theme(s1,x1) & in(e1,x2) & n_chair(x2) & of(x2,x3) & n_rocking(x3) & Actor(e1,x1) & v_sit(e1))