多项选择题
A.All control files are opened.
B.All redo log files are opened
C.The password file is opened.
D.The parameter file is opened.
E.All online data files are opened.
单项选择题 Anyonewhoknowsjustthehostnameandthelistenernamecanhavefullcontroloverthelistener.Theycanstopthelistenerandalsoobtaindetailedinformationaboutthelistener，database，andtheconfigurationoftheapplication.Howwouldyouavoidthisscenario？（）
单项选择题 Youareworkingona24x7（available24hoursperday，7daysperweek）productiondatabase.Anoperatingsystem（OS）userdeletesthealertlogfileaccidentally.Whichstatementinthisscenarioistrue？（）
单项选择题 Becauseofapoweroutage，instancefailurehasoccurred.Fromwhatpointintheredologdoesrecoverybeginandwheredoesitend？（）