复发性口腔溃疡治疗措施中哪项效果最佳

A．口腔局部消炎、止痛，促愈合

B．手术切除

C．注射转移因子或口服左旋咪唑

D．尽可能找出与发病有关的全身和局部因素，加以治疗

E．补充营养

Frame Relay is simplified form of (66) , similar in principle to (67) , 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 (68) . Most Virtual Circuits are (69) , which means that the network provider sets up all DLCI connections at subscription time. (70) are also part of the Frame Relay specification. They privide a link that only lasts only as long as the session.

69（）

A．Permanent Circuits

B．Permanent Virtual Circuits

C．Switched Virtual Circuits

D．Switching Circuits