主格：i you he she they
宾格：me you him her them
形容词性物主代词：my your his her their
用法：
1.我爱你
I love you.
她爱他
she loves him.
所以,主格是发出动作的人或物,而宾格是接受动作,受动作影响的对象,也就是通常放在动词后的名词.
名词性物质代词的用法：
Their books are borrowed by him.
他们的书被他借走了.
他们的就是their
这里的“他”原本是动作发出者,但是因为在被动句里,所以就必须用宾格“him”.