疑问副词与关系副词的区别?

疑问副词用来问特殊疑问句（特殊疑问词加一般疑问句?）关系副词引导定语从句。关系副词：when引导定语从句,表示时间,其先行词往往是表示时间的名词（如：time,day,hour,year等）．eg。October 1,1949 was the day when the People's Republic of China was founded。(when表示时间)where引导定语从句,表示地点,其先行词往往是表示地点的名词(如：place,room,house,street,area等)．eg。This is the place where my mother was born。(where表示地点)why引导定语从句,表示原因,常用在先行词reason后面．eg。I don't know the reason why she looks unhappy today。(why 表示原因)