A little white dog with long fur stands on his hind legs.
The dog is standing on four legs.
Hind legs mean a dog's two feet closest to its tail.  A dog cannot be on its hind legs and four legs at the same time
exists e1 s1 s2 s3 x1 x2 x3 x4.(on(e1,x3) & n_leg(x3) & of(x3,x4) & n_hind(x4) & of(x3,x1) & n_male(x1) & Actor(e1,x1) & v_stand(e1) & with(x1,x2) & n_fur(x2) & a_long(s3) & Theme(s3,x2) & n_dog(x1) & a_white(s2) & Theme(s2,x1) & a_little(s1) & Theme(s1,x1))
exists e1 x1 x2.(n_dog(x1) & on(e1,x2) & n_leg(x2) & card_eq_4(x2) & Actor(e1,x1) & v_stand(e1))