Four teenagers standing next to a bus and talking and laughing.
Four teenagers are quiet and have somber expressions.
If people are talking, they are not quiet. If people are laughing, they do not have somber expressions.
exists e3 e2 e1 x1 x2 x3 x4.(Actor(e3,x4) & v_laugh(e3) & n_teenager(x4) & card_eq_4(x4) & Actor(e2,x3) & v_talk(e2) & n_teenager(x3) & card_eq_4(x3) & to(e1,x2) & n_bus(x2) & r_next(e1) & Actor(e1,x1) & v_stand(e1) & n_teenager(x1) & card_eq_4(x1))
exists e1 s1 s2 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x2) & v_have(e1) & n_expression(x3) & a_somber(s2) & Theme(s2,x3) & n_teenager(x2) & card_eq_4(x2) & Theme(s1,x1) & a_quiet(s1) & n_teenager(x1) & card_eq_4(x1))