---- It is the second time that I _________ to Shanghai.

----- What great changes! It’s ten years since I _______ there last time.

A．have been; went

B．had been; went

C．am; had been

D．come; had been

古罗马的市政官规定：上市的奴隶须用牌子写明各奴隶的国籍、性别、年龄、技能和有无疾病等，并挂在胸前，事后如发现有出入，允许买主请求减价或解除契约。此规定体现了罗马法的主要现实意义是：（）

A.协调罗马公民间的关系

B.适应商品经济的客观需要

C.保护奴隶的正常交易

D.维护奴隶主的经济利益