在楚汉战争中，刘邦能打败项羽的原因有
①善于用人 ②有关中作为后方 ③约法三章 ④军力强大 [ ]
A．①②③
B．②③④
C．①③④
D．①②④
答案：A
Open Shortest Path First(OSPF)is a (29) routing algorithm that (30) work done on the OSI IS-IS intradomain routing protocol. This routing, as compared to distance-vector routing, requires (31) processing power. The Dijkstra algorithm is used to calculate (32) OSPF routing table updates only take place when necessary, (33) at regular intervals.
31（）
A．more
B．less
C．same
D．most
