TCP/IP是由一系列协议组成的协议组。共分几层()
A.三层
B.五层
C.四层
D.六层
参考答案:C
Tigers in the state often compete with villagers living close to the reserves for resources, often________ direct conflict.
A.leading to
B.relying on
C.standing for
D.consisting of
井巷的分道口应有路标,注明其所在地点及通往地面出口的方向。所有井下安全员,均应熟悉安全出口。