A boy tosses a rock across a river.
The girl twirled the baton.
A boy is not a girl, and tosses and twirled are incompatible together.
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_toss(e1) & across(x2,x3) & n_river(x3) & n_rock(x2) & n_boy(x1))
exists e1 x1 x2.(n_baton(x2) & n_girl(x1) & Theme(e1,x2) & Actor(e1,x1) & v_twirl(e1))