her hers的区别还有on with to in 的区别to和for的用法

her是形容词性物主代词,用来修饰名词,可以做定语.hers是名词性物主代词,在句中可以做主语,宾语,表语.举例如下：
This is her book.
This is my pen,but that is hers.
Hers is better.

补充说明楼上的一下，hers后面不能再加所代指的东西了
例如：
Whose book is there?
It's her book./It's hers.(不能说成:It's hers book!!!)