The Simple Network Management Protocol (SNMP)is an  （）protocol that facilitates the exchange of management information between  （） . It is part of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite. SNMP enables network  （） to manage network performance, find and sole network problems, and plan for  （） . An SNMP-man-aged network consists of three key components: managed devices, （） , and network-management systems.

the exchange of management information between（）

A．network stations

B．network clients

C．network devices

D．network servers

下述低频电疗法中，"治疗时将2个电极对置或并置于痛点、穴位、运动点、神经走行部位或神经节段。根据治疗需要选择电流频率、波宽、治疗时间"属于（）

A.电化学疗法

B.电兴奋疗法

C.间动电疗法

D.痉挛肌电刺激

E.经皮神经电刺激疗法