A man is smiling while standing behind a podium.
man is sitting
man can't be both standing and sitting
exists e1 e2 x1 x2.(while(e1,e2) & behind(e2,x2) & n_podium(x2) & Actor(e2,x1) & v_stand(e2) & Actor(e1,x1) & v_smile(e1) & n_man(x1))
exists e1 x1.(Actor(e1,x1) & v_sit(e1) & n_man(x1))