A boy and a girl are swinging on a swing set in a park.
Brother and sister playing together at the neighborhood park
You can not infer they are brother and sister.
exists e1 e2 x1 x2 x3 x4 x5 x6.(on(e1,x4) & in(e2,x6) & n_park(x6) & Theme(e2,x5) & v_set(e2) & (x4 = x5) & n_swing(x4) & Actor(e1,x1) & v_swing(e1) & subset_of(x3,x1) & n_girl(x3) & subset_of(x2,x1) & n_boy(x2))
exists s1 s2 s3 x1 x2 x3 x4 x5.(n_park(x4) & of(x4,x5) & n_neighborhood(x5) & ne_nam_brother(x1) & a_topic(s1) & subset_of(x2,s1) & at(s3,x4) & Theme(s3,x3) & a_together(s3) & (x2 = x3) & n_playing(x2) & a_sister(s2) & Theme(s2,x2) & subset_of(x1,s1))