多项选择题
A.ALTER DATABASE ARCHIVELOG；B.ALTER DATABASE BEGIN BACKUP；C.ALTER DATABASE END BACKUP；D.ALTER SYSTEM ARCHIVE LOG CURRENT；
A.SHUTDOWN NORMAL；B.SHUTDOWN TRANSACTION；C.SHUTDOWN IMMEDIATE；D.SHUTDOWN ABORT；
A.create or replace view 语句B.create or replace sequence语句C.create or replace synonym语句D.create or replace function语句