A.無線覆蓋B.點(diǎn)對(duì)點(diǎn)或點(diǎn)對(duì)多C.中繼連接D.其余三項(xiàng)都是
A.底層B.表層C.接入層D.接觸層
A.0.6~0.8MPaB.0.45~0.60MPaC.0.5~0.7MPaD.0.5~0.9MPa