You haven't seen the film,I haven't seen it ,either---------- ----------- us have seen the film

You haven't seen the film,I haven't seen it ,either---------- ----------- us have seen the film
You haven't seen the film,I haven't seen it ,either
---------- ----------- us have seen the film

You haven't seen the film,I haven't seen it ,either---------- ----------- us have seen the film
【Neither of】us have seen the film
both用于2者都肯定,neither用于2者都否定.