多项选择题 YounoticethatyourRMANscriptusedtocopythedatafiles，controlfiles，andarchivedredologfilesisperformingveryslowly.WhichtwochangesmightyouwanttoincludeinyourRMANscripttospeeduptheCOPYcommands？（）

单项选择题 Whichstatementistrueregardingremotearchivelogfiledestinations？（）

多项选择题 You issue this SQL command to perform an online backup of the USER_DATA tablespace：ALTER TABLESPACE user_data BEGIN BACKUP；Next， you issue an operating system command to back up user_data01.dbf， the file that belongs to the USER_DATA tablespace. You then experience an instance failure.  Which three statements are true？（）