根据对话内容，从方框中选出恰当的句子补全对话。

A. Yes, please. B. At most five. C. How long may I keep then? D. If not, you'll have to pay a fine. E. You can check for them on the computer first.

A: May I help you?

B: I'd like to borrow some books on Western culture and customs. How can I find them?

A:

B: OK. How many books may I borrow at a time?

A:

(Ten minutes later)

B: I'd like to borrow these three books

A: Two weeks.

B: Two weeks? I'm afraid I can't return them until I've finished my project.

A: In that case, you must renew them before they're due. It's 0.5 yuan a day for each book.