关于英语定语从句的关系代词问题20130716001定语从句关系代词Who是指人,可以充当主语、宾语、表语.我不是很理解什么叫做Who可以充当【主语】和【宾语】及【表语】,各位大虾能否就【主、宾、表】列出三个例句并稍微向在下讲解呢?

①.who作主语.I met the person who is your brother yesterday.
②.who作宾语.She is the one who(whom) I only love.
③.who作表语She is no longer the woman who she used to be
Ⅰ.who是否作主语需要根据从句缺少什么成分来判断。你看像第一句“is your brother”明显缺少主语，即“谁is your brother”.因为从句缺少成份所以因从关系代词中找替代词。而这句话明显是缺少“人”做主语所以用who来引导其后的定语从句.
Ⅱ.首先注意，who在引导定语从句做宾语时，即可为who也可为whom（whom只可用于宾语情况）。句中I only love明显缺少一个love的对象，所以缺少指人的宾语，所以填who或者是whom.
Ⅲ.做表语也是根据从句的缺少成分进行判断.

【主语】
I love him who is called Daniel
【宾语】
I love him who I met yesterday
【表语】
I love him who the winner of this match will be.

首先要明白“定语从句"指整个从句作定语,起修饰前面的名词或代词（即先行词）的作用,这时此从句就需要关系词例如who 来引导,以下为例：

who做主语指充当从句主语,如：

Is he the man who wants to see you ? 其中,who在从句who  wants to see you 中是动作执行者,做主语,而整个从句修饰先行词 the man .woman

who 做宾语指充当从句宾语,如：

He is the man who / whom I talked with yesterday.其中,who 做从句中短语 talked  with 的宾语,而整个从句修饰先行词 the man .若介词with 提前,关系代词只能用whom,即He is the man with  whom I talked yesterday.

who做表语指充当从句表语,如：

She is no longer the  woman who she used to be. 此句中who做系动词be 的表语.

希望多你有帮助.