The metric assigned to each network depends on the type of protocol. Some simple protocol, like RIP, treats each network as equals. The（1）of passing through each network is the same; it is one（2）count. So if a packet passes through 10 network to reach the destination, the total cost is 10 hop counts. Other protocols, such as OSPF, allow the administrator to assign a cost for passing through a network based on the type of service required.A（3）through a network can have different costs (metrics). For example, if maximum（4）is the desired type of service, a satellite link has a lower metric than a fiber-optic line. On the other hand, if minimum（5）is the desired type of service, a fiber-optic line has a lower metric than a satellite line. OSPF allow each router to have several routing table based on the required type of service.

5（）

A．bandwidth

B．efficiency

C．availability

D．delay

目前我国临床实验室测定酶活性浓度推荐温度为（）

A.（25±0.1）℃

B.（37±0.5）℃

C.（37±0.3）℃

D.（37±0.1）℃

E.（37±1）℃