线路停送电操作时应注意哪些事项？
肾小管分泌作用
中国梦与香港、澳门、台湾密不可分。历史已经证明，香港、澳门、台湾的命运与大陆密不可分。
链条的约束属于（）约束。 柔性。 刚性。 固定端。 二力杆。
Which two statements are true about the rendezvo us point (RP) in a multicast network?（） The multicast sources must register with the RP to form the multicast distribution tree.。 An RP is required only in networks running Protocol Independent Multicast dense mode (PIM DM).。 The mu lticast receivers must register with the RP to form the multicast distribution tree.。 An RP is required only in networks running Protocol Independent Multicast sparse mode (PIM SM).。 An RP is required only in networks running Protocol Independent Mu lticast sparse - dense mode (PIM - SDM).。 To form the multicast distribution tree, the multicast sources register with and the receivers join the RP.。
测量孕妇的宫低高度、腰围，下列述正确的是（）
