Several children are playing in water fountains.
John is the only child playing in a water fountain.
If John is the only child playing in the fountain, there could not be several children also playing.
exists e1 s1 x1 x2 x3.(in(e1,x2) & n_fountain(x2) & of(x2,x3) & n_water(x3) & Actor(e1,x1) & v_play(e1) & n_child(x1) & a_several(s1) & Theme(s1,x1))
exists p1 x1 x2 x3.(all x6 x7.((n_playing(x6) & of(x6,x7) & n_child(x7)) -> (x2 = x6)) & n_playing(x2) & of(x2,x3) & n_child(x3) & ne_per_john(x1) & exists x4 x5.((x1 = x2) & in(x2,x4) & n_fountain(x4) & of(x4,x5) & n_water(x5)))