Open Shortest Path First(OSPF)is a (71) routing algorithm that (72) work done on theOSI IS-IS intradomain routing protocol. This routing, as compared to distance-vector routing,requires (73) processing power. The (74) algorithm is used to calculate mutes. OSPFrouting table updates only take place when necessary, (75) at regular intervals.

A．distance-vector

B．link-state

C．flow-based

D．selective flooding

聚四氟乙稀薄膜当温度超过（）时，燃烧时将生成有强烈毒性的气态氟化物。

A、150℃；

B、180℃；

C、240℃；

D、320℃。