four kids are crossing a river by stepping stones
A group of kids riding motorcycles.
Riding a motorcycle is not compatible with crossing a river.
exists e2 e1 x1 x2 x3.(by(e1,e2) & Theme(e2,x3) & Actor(e2,x1) & v_step(e2) & n_stone(x3) & Theme(e1,x2) & Actor(e1,x1) & v_cross(e1) & n_river(x2) & n_kid(x1) & card_eq_4(x1))
exists e1 x1 x2 x3 x4.(a_topic(x1) & of(x1,x2) & Theme(e1,x4) & Actor(e1,x3) & v_ride(e1) & n_motorcycle(x4) & (x2 = x3) & n_kid(x2) & n_group(x1))