设备检修应坚持（）的原则，设备经常保持健康状态。
参考答案：预防为主，计划检修，应修必修，修必修好，统一配合，避免重复停电
侵蚀性葡萄胎血性转移的部位主要是（）
A．肺和脑
B．肺和 * *
C．胃肠道和肝
D．肺和胃肠道
E．子宫旁血管和 * * 静脉丛
Open Shortest Path First(OSPF)is a (72) routing algorithm that (73) work done on theOSI IS-IS intradomain routing protocol. This routing, as compared to distance-vector routing,requires (74) processing power. The (75) algorithm is used to calculate mutes. OSPFrouting table updates only take place when necessary, (76) at regular intervals.
A．Bellman-Ford B．Ford-Fulkerson C．Dijkstra D．RIP
