Koko: Mr. Zhang, I'm going to borrow some books from our library. Can you give me some suggestions?
Mr.Zhang: You can borrow two books at a time. But you must return it in two weeks.
Koko: Can I renew the books?
Mr.Zhang: Yes, this duration can be extended for two more weeks. But you must inform the librarian by email ahead of the deadline.
Koko: That is to say I can borrow the books for four weeks at most.
Mr.Zhang: That's right. Please take good care of the books. Keep the books neatly. And you must be quiet in the library.
Koko: I will remember that. Thank you very much.