汲冢书
松弛说
时间知觉
非交互作用
In which circumstance are multiple copies of the same unicast frame likely to be transmitted in a switched LAN?（） after broken links are re-established。 in an improperly implemented redundant topology。 when upper-layer protocols require high reliability。 during high traffic periods。 when a dual ring topology is in use。
非报纸广告的设计准则是（）
