三方柱的对称型是L33L24PC.
参考答案:错
数据库管理系统(DBMS)的层次结构中,数据存取层的处理对象是( )
A.单个元组
B.日志
C.系统缓冲区
D.索引
Combustible gas indicators measure the presence of combustible gas as a percentage of the().
A.flash point
B.upper explosive limit
C.lower explosive limit
D.fire point