Some firefighters check a vehicle.
Firefighters are rescuing a cat from the tree.
The firefighters can't be checking a vehicle and rescuing a cat from the tree simultaneously.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_check(e1) & n_vehicle(x2) & n_firefighter(x1))
exists e1 x1 x2 x3.(n_tree(x3) & from(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_rescue(e1) & n_cat(x2) & n_firefighter(x1))