the library sent three inform notices on the fines incurred

图书馆发出三条通知,要求对于过期不换书的事宜处以罚款
notices on the fines ,on the fines 是介词短语后置,修饰通知
然后,incurred ,过去分词,定语后置,修饰罚款
on the overdue books,介词短语做状语,对于逾期不换的图书