掘进巷道贯通后,道先应干什么?
参考答案:
立即调整通风系统,防止瓦斯积聚。
In order to get names of schoolboys(SEX='M')whose age=22, from a relation S(SNO,SNAME,SEX,AGE),which of the following expressions is (are) correct Ⅰ.πsname(σsex='M'^age=22(S)) Ⅱ.σsex='M'^age=22(πsname(S))
A. Ⅰ only
B. Ⅱ only
C. Ⅰand Ⅱ
D. neither
参照图5.89和图5.90,为Server1网卡eth1配置Internet协议的属性参数。 IP地址: (2) 子网掩码: (3)
为Server1网卡eth0配置Internet协议的属性参数。 IP地址: (4) 子网掩码: (5) 默认网关: (6)