A choir sings outside together.
A choir singing together.
Both sentences state that the choir are singing together
exists s1 s2 x1 x2 x3.(Theme(s2,x1) & a_together(s2) & Theme(s1,x3) & a_outside(s1) & (x1 = x3) & n_sing(x1) & of(x1,x2) & n_choir(x2))
exists e1 p1 x1 x2.(a_topic(x1) & exists s1.(Theme(s1,x2) & a_together(s1)) & Topic(e1,p1) & Actor(e1,x2) & v_sing(e1) & (x1 = x2) & n_choir(x1))