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 should 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 should 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 should be quiet in the library.

Koko: I will remember that. Thank you very much.