多项选择题
A. Only data files and the control file are backed up.
B. Archived redo logs are backed up only if the database is open during the backup.
C. The backup is deleted after one day，regardless of the default retention policy settings.
D. The backup becomes obsolete after one day，regardless of the default retention policy settings.
单项选择题 You want to perform the following operations for the DATA ASM disk group： -Verify the consistency of the disk. -Cross-check all the file extent maps and allocation tables for consistency. check whether the alias metadata directory and file directory are linked correctly. -Check that ASM metadata directories do not have unreachable allocated blocks. Which command accomplishes these tasks（）？
多项选择题 Whichtwostatementsarecorrectaboutdatabasetransportation？（）
多项选择题 Whichtwostatementsaretruewithrespecttothemaintenancewindow？（）.