SMART原则
参考答案：目标必须是具体明确的，目标必须是可以衡量的，目标必须是可以达到的，目标必须和其他目标具有相关性，目标必须具有明确的截止期限。
Frame Relay is simplified form of (71) , similar in principle to (72) , in which synchronous, frames of data are routed to different destinations depending on header information . Packets are routed throught one or more Virtual Circuits known as (73) . Most Virtual Circuits are (74) ,which means that the network provider sets up all DLCI connections at subscription time. (75) are also part of the Frame Relay specification . They privide a link that only lasts only as long as the session.
A．Permanent Circuits
B．Permanent Virtual Circuits
C．Switched Virtual Circuits
D．Switched Circuits
手工电弧焊焊接电缆采用多股细（）制成。
A.钢丝
B.铜丝
C.铝丝
