Two children eating food.
Two children are drinking water.
You cannot be eating if you are drinking it is only possible to do one of those activities at a time.
exists e1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_eat(e1) & n_food(x3) & (x1 = x2) & n_child(x1) & card_eq_2(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_drink(e1) & n_water(x2) & n_child(x1) & card_eq_2(x1))