你这里引用的资料好像是我以前在本网中的解答内容，其中有误。建议你不要采用这种观点。这部分内容我修改如下：

定语从句修饰指人的名词且关系代词在定语从句中作归属性表语或宾补，限制性定语从句中关系代词只能用that或者省略that，不能用who，也不能用which。非限制性定语从句关系代词只能用which，不能用who或that。

如果关系代词在定语从句中作确认性表语，则无论限制性还是非限制性定语从句，关系代词都用who，不用which或that。例如：

He is no longer the man that he used to be. 正确。限制性定语从句，归属性表语，关系代词用that。

He is no longer the man he used to be. 正确。限制性定语从句，归属性表语，省略了关系代词that。

He is no longer the man who he used to be. 错误。限制性定语从句，归属性表语，关系代词误用了who。

He is no longer the man which he used to be. 错误。限制性定语从句，归属性表语，误用了which。

He is a teacher, which I am not. 正确。非限制定语从句，归属性表语，关系代词用which。

He wasn't the person who I had thought he was. 正确。限制性定语从句，确认性表语，关系代词用who。

He denied he was Tom, who I though he was. 正确。非限制性定语从句，确认性表语，关系代词用who。