---Is your father still in Shanghai?

---Yes, he _________there for two weeks.

A．has gone to

B．has gone

C．has been in

D．has been

SQL通常不提供下列哪一种操作

A．修改索引定义

B．修改视图定义

C．修改索引定义和修改视图定义

D．修改表定义