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．Bellman-Ford

B．Ford-Fulkerson

C．Dijkstra

D．RIP

心电图上平均R-R间隔为0.75秒，其心率为( )。

A．60次/分
B．70次/分
C．80次/分
D．90次/分
E．100次/分