A speaker is giving a speech at a formal event.
The speaker didn't make the event.
the speaker cannot give a speech at a event he didn't make
exists e1 s1 x1 x2 x3.(at(e1,x3) & n_event(x3) & a_formal(s1) & Theme(s1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_give(e1) & n_speech(x2) & n_speaker(x1))
exists x1 x2.(n_event(x2) & n_speaker(x1) & -exists e1.(Theme(e1,x2) & Actor(e1,x1) & v_make(e1)))