To learn English well, we should find opportunities to hear English      as much as we can.  [ ]

A. spoken

B. speaking

C. speak  

D. to speak

数据库设计分为以下6个设计阶段：需求分析阶段、______、逻辑设计阶段、物理设计阶段、实施阶段、运行和维护阶段。