HY-40钻机个模块之间的液压管线用（）连接。
A、扩口式接头
B、焊接式接头
C、卡套式接头
D、快速接头
参考答案：D
It is said that _________ mobile telephone was invented not very long ago.
A．a
B．the
C．one
D．不填
输油管线始、末端和分支处的接地电阻不应大于（）Ω；卸油防静电接地不应大于100。
A.20
B.30
C.40
D.50
