A man is giving a speech.
A man is speaking to his graduating class.
A man giving a speech does not mean he's speaking to his graduating class.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_give(e1) & n_speech(x2) & n_man(x1))
exists e2 e1 x1 x2.(to(e1,x2) & n_class(x2) & Actor(e2,x2) & v_graduate(e2) & of(x2,x1) & n_male(x1) & Actor(e1,x1) & v_speak(e1) & n_man(x1))