单项选择题
A.Running B.Nomount C.Mount D.Open
A.无屏蔽双绞线 B.屏蔽双绞线 C.粗同轴电缆 D.细同轴电缆
A.select*from scott.wz where wunit is null and rownum＜5； B.select*from myuser.wz where wunit = null and rownum＜5； C.select*from myuser.wz where wunit is null and rownum＜6； D.select*form scott.wz where wunit is null and rownum＜6;