单项选择题
A.You performed rollback after commit.
B.If a log switch occurs in your database.
C.Thearchiverfails to generate an archived log file.
D.Instance recovery fails to find one of the redo log files.
E.A long-running query is unable to get read-consistent image.
F.If you perform manual undo management operations in auto mode.
单项选择题 YouworkasadatabaseadministratorforSupportcenter.cn.Youaddedatablespacetoyourdatabase.Becauseofthechangestothephysicalstructureofyourdatabase，youperformedabackupofthecontrolfiletotrace.Afterthis，youlostonlythecontrolfilesandtheinstanceabortedduetoahardwarefailure.Howwouldyouproceedtorecoverthedatabase？（）
单项选择题 YouworkasadatabaseadministratorforSupportcenter.cn.Clientconnectionrequestsarefailingbecausethelistenerisnotresponding.Youwanttoforwardclientconnectrequeststoanotherlistenerifonelistenerisnotresponding.Howdoyouachievethis？（）
多项选择题 YouworkasadatabaseadministratorforSupportcenter.cn.YourdatabaseisintheMOUNTstateandyouexecutethefollowingcommandtoopenitALTERDATABASEOPEN；Whattwoactionsareperformedasaresultofthiscommand？（）