An impromptu toast among friends.
A man sits alone.
A toast among friends can not occur while a man sits alone.
exists s1 x1 x2.(a_topic(x1) & among(x1,x2) & n_friend(x2) & n_toast(x1) & a_impromptu(s1) & Theme(s1,x1))
exists e1 s1 x1.(a_alone(s1) & Manner(e1,s1) & Actor(e1,x1) & v_sit(e1) & n_man(x1))