A little boy on a green sled at night.
A boy is iceskating.
One cannot be iceskating and sledding simultaneously.
exists e1 s1 x1 x2 x3 x4.(a_topic(x1) & on(x1,x2) & at(e1,x4) & n_night(x4) & Theme(e1,x3) & v_sled(e1) & (x2 = x3) & n_green(x2) & n_boy(x1) & a_little(s1) & Theme(s1,x1))
exists e1 x1.(Actor(e1,x1) & v_iceskate(e1) & n_boy(x1))