多项选择题 While Monitoring the space usage in your database that is in ARCHIVELOG mode you observed   that the flash recovery area does not have enough free space to accommodate any more files and you do not have necessary permissions to add more space to it.  Identify the two events that can occur in the event of a log switch？（）

单项选择题 Your database instance is running. You are not able to access Oracle Enterprise Manager Database Control because the listener is not started.  Which tool or utility would you use to start the listener？（）

多项选择题 WhichtwostatementsaretrueaboutencryptingRMANbackup？（）