The bird is carrying a plant in its mouth while flying.
A bird is carrying a fish in it's mouth.
A bird cannot carry a plant and a fish in its mouth simultaneously.
exists e1 e2 x1 x2 x3.(n_mouth(x3) & of(x3,x1) & n_thing(x1) & n_bird(x1) & while(e1,e2) & Actor(e2,x1) & v_fly(e2) & Theme(e1,x2) & Actor(e1,x1) & v_carry(e1) & in(x2,x3) & n_plant(x2))
exists e1 p1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_carry(e1) & exists x4.((x3 = x4) & n_mouth(x4)) & (x2 = x3) & in(x2,x1) & n_thing(x1) & n_fish(x2) & n_bird(x1))