多项选择题
A.1000Base-CX
B.1000Base-TX
C.1000Base-SX
D.10Base-T
E.1000Base-T
F.1000Base-LX
单项选择题 WhichofthefollowingnetworkdevicesoperatesonLayer1oftheOSImodel？（）
单项选择题 Anetworktechnicianisinstallingaseriesofthreeaccesspointstocovertheentirewingofabuilding.Eachaccesspointhasawiredconnectionand802.11gisbeingusedforthewirelesstransmission.Whichofthefollowingchannelsshouldbeusedfortheaccesspoints？（）
单项选择题 Atechniciannoticesthatwhentryingtopingaworkstationbynetworknametheworkstationdoesnotreplybackoverthenetwork.TheworkstationispartofthedomainandisabletogettotheInternet.Whichofthefollowingisthecauseoftheproblem？（）