Three people are in a sailboat on the water.
A family is sailing.
We don't know if the three people are family.
exists p1 x1 x3.(n_water(x3) & exists x2.(in(x1,x2) & on(x2,x3) & n_sailboat(x2)) & n_people(x1) & card_eq_3(x1))
exists p1 x1.(exists x2.((x1 = x2) & n_sailing(x2)) & n_family(x1))