Two girls are walking along the street and talking.
The two girls that were walking together were talking about school
Just that two girls are walking along on the street and talking doesn't imply they are talking about school.
exists e2 e1 x1 x2 x3.(n_street(x2) & Actor(e2,x3) & v_talking(e2) & n_girl(x3) & card_eq_2(x3) & along(e1,x2) & Actor(e1,x1) & v_walk(e1) & n_girl(x1) & card_eq_2(x1))
exists e1 e2 s1 x1 x2 x3.(n_girl(x1) & card_eq_2(x1) & about(e2,x3) & n_school(x3) & Actor(e2,x1) & v_talk(e2) & a_together(s1) & Manner(e1,s1) & Actor(e1,x2) & v_walk(e1) & (x1 = x2))