悬臂式和锚定式挡土墙属于（）
A、扶壁式
B、桩、墙式
C、重力式
D、固定式
参考答案：B
数据库设计的步骤包括需求分析、确定需要的表、确定所需字段、确定主键、( )。
The disinfection of various compartments in a vessel by filling with a gaseous agent to destroy rats and all insects pests which act as germ carriers means（）.
A.displacement
B.fumigation
C.discharging
D.compensation
