Some young adults sip a yellow-green drink.
the people are women
The first sentence does not indicate what gender the people are, so we can't say they are women.
exists e1 s1 s2 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_sip(e1) & n_drink(x2) & a_yellow-green(s2) & Theme(s2,x2) & n_adult(x1) & a_young(s1) & Theme(s1,x1))
exists p1 x1.(n_people(x1) & exists x2.((x1 = x2) & n_woman(x2)))