I was very surprised at the way___ he spoke at the meeting.为什么不填,要用which的好话用in which

I was very surprised at the way___ he spoke at the meeting.为什么不填,要用which的好话用in which
I was very surprised at the way___ he spoke at the meeting.为什么不填,要用which的话用in which,in which不等于where吗?有点糊涂啊