there是副词,在主句中充当后置定语,修饰stay.
her stay there即“她在那里/那儿的逗留”.
副词可以做定语,但一般都做后置定语.
再如：
I hate the neighbour upstairs/downstairs.我讨厌楼上/楼下的邻居.
The people there are friendly.那里的人们很友好.
如果对你有所帮助,请点击我回答下面的“选为满意回答”按钮,