单项选择题
A.create recovery catalog
B.create catalog
C.build catalog
D.catalog create
E.mount catalog
单项选择题 WhatcommandwouldyouusetosetapersistentsettinginRMANsothatbackupsareallwrittentoatapedevice?（）
单项选择题 Whatfeaturecomesintoplaytohelpensurethecompletionofthebackupshouldoneofthreebackupdevicesfailduringabackupthatisusingthreedifferentchannels?（）
单项选择题 Whichdynamicviewdisplaysthestatusofblock-changetracking?（）