–Why didn’t Mary come to John’s birthday party last night?

–She ______ to, but her dad simply would not let her out so late at night.

A.wants      B. wanted      C. has wanted

分布式数据库系统不具有的特点是______。

A．分布式

B．数据冗余

C．数据分布性和逻辑整体性

D．位置透明性和复制透明性