单项选择题 WhichstatementaboutusingRMANstoredscriptsistrue？（）

单项选择题 Whichtuningtoolrecommendshowtooptimizematerializedviewssothattheseviewscantakeadvantageofthegeneralqueryrewritefeature？（）

单项选择题 Observe the following warning in an RMAN session of your database instance：   WARNING： new failures were found since last LIST FAILURE command   Which statement describes the scenario that must have produced this warning？（）