Seven people wearing green T-shirts are walking on the beach and one of them is waving.
Seven women wearing light green T-shirts are walking on the beach and one of them is waving.
i would think it were seven men walking and not women. That can't be implied from the information given.
exists e1 e3 e2 s1 x1 x2 x3 x4 x5.(n_thing(x4) & n_beach(x4) & Actor(e3,x5) & v_wave(e3) & of(x5,x4) & n_thing(x5) & card_eq_1(x5) & on(e2,x4) & Actor(e2,x1) & v_walk(e2) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_t-shirt(x3) & a_green(s1) & Theme(s1,x3) & (x1 = x2) & n_people(x1) & card_eq_7(x1))
exists e1 e3 e2 s1 s2 x1 x2 x3 x4 x5.(n_thing(x4) & n_beach(x4) & Actor(e3,x5) & v_wave(e3) & of(x5,x4) & n_thing(x5) & card_eq_1(x5) & on(e2,x4) & Actor(e2,x1) & v_walk(e2) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_t-shirt(x3) & a_green(s2) & Theme(s2,x3) & a_light(s1) & Theme(s1,x3) & (x1 = x2) & n_woman(x1) & card_eq_7(x1))