premise: Children play in the sand surrounded by a sand structure with a lot of window like openings.
hypothesis: The children playing in the sand all know each other.
explanation_1: As the amount of children isn't stated there could be between 2 and thousands at the beach. It's possibly that two might not even know each other and might just be playing because they're both kids.
explanation_2: Just because a bunch of children are playing in the same sand doesn't mean they all know each other.
explanation_3: Children play in the sand surrounded by a sand structure doesn't mean that they all know each other.
premise_logic: exists e1 x1 x2 x3 x4 x5 x6 x7 x8.(a_topic(x1) & with(e1,x6) & of(x6,x7) & like(x7,x8) & n_opening(x8) & n_window(x7) & n_lot(x6) & Actor(e1,x5) & n_structure(x5) & of(x5,x3) & n_sand(x3) & n_sand(x3) & Theme(e1,x4) & v_surround(e1) & (x1 = x4) & in(x1,x3) & n_play(x1) & (x1 = x2) & ne_nam_children(x2))
hypothesis_logic: exists e1 x1 x2 x3.(n_sand(x3) & n_child(x1) & all x4.(n_other(x4) -> exists e2 s1.(a_all(s1) & Manner(e2,s1) & Theme(e2,x4) & Actor(e2,x1) & v_know(e2))) & in(e1,x3) & Actor(e1,x2) & v_play(e1) & (x1 = x2))
premise_sim: exists e1 x1 x2 x3 x4 x5 x6 x7 x8.(with(e1,x6) & v_surround(e1) & of(x6,x7) & of(x5,x3) & ne_nam_children(x2) & n_window(x7) & n_structure(x5) & n_sand(x3) & n_play(x1) & n_opening(x8) & n_lot(x6) & like(x7,x8) & in(x1,x3) & a_topic(x1) & Theme(e1,x4) & Actor(e1,x5) & (x1 = x4) & (x1 = x2))
hypothesis_sim: exists e1 x1 x2 x3.(v_play(e1) & n_sand(x3) & n_child(x1) & in(e1,x3) & all x4.(exists e2 s1.(v_know(e2) & a_all(s1) & Theme(e2,x4) & Manner(e2,s1) & Actor(e2,x1)) | -n_other(x4)) & Actor(e1,x2) & (x1 = x2))