数据库应用系统的设计应该具有对于数据进行收集、存储、加工、抽取和传播等功能，即包括数据设计和处理设计，而 【17】 是系统设计的基础和核心。

Speaker A: I’d like to buy a copy of Professor Franklin’s book on shells.
Speaker B: （）。

A. Are you one of Professor Franklin’s students

B. But I like his book on fish better than that on shells.

C. I’m sorry, sir. That book has been out of print for some time now.

D. Will you pay over there at the cashier