There are two dogs playing with each other.
The dogs are brother and sister.
Sentence 1 is missing dogs are brother and sister.
exists p1 x1 e1 x2 x3.((x1 = x2) & all x4.(n_other(x4) -> with(e1,x4)) & Actor(e1,x3) & v_play(e1) & (x2 = x3) & n_dog(x2) & card_eq_2(x2))
exists p1 x1.(n_dog(x1) & exists x2 x3 x4.((x1 = x2) & subset_of(x4,x2) & n_sister(x4) & subset_of(x3,x2) & n_brother(x3)))