I really don't know if I can borrow the book in __A the library of the school B the school's libraryc the library of schools d the school library 答案选最后一个,

I really don't know if I can borrow the book in __
A the library of the school B the school's library
c the library of schools d the school library 答案选最后一个,

就是名词school作了名词 library 的定语,这种现象就是“名词定语”,这样很简洁,前面三种表达方式繁琐、不被人们所接受.

AD
both ok