缺隙两端各有一基牙，一侧为可动连接体、一侧为不动连接体的固定桥称为

A．双端固定桥
B．种植体固定桥
C．应力中断式固定桥
D．复合固定桥
E．粘结固定桥

Open Shortest Path First(OSPF)is a (71) routing algorithm that (72) workdone on the OSI IS-IS intradomain routing protocol．This routing，as compared todistance—vector routing，requires (73) processing power．The Dijkstra algorithm is usedto calculate (74) OSPF routing table updates only take place when necessary， (75) atregular intervals．

A．but rather
B．rather too
C．rather than
D．rather that