单项选择题
Which of the following commands will fail？（）
A. report schema B. report need backup C. report need backup days 3 D. report user E. report obsolete
单项选择题 Whatisthepurposeofthecatalogcommand？（）
单项选择题 Whatisanobsoletebackupset？（）
多项选择题 Whatisthepurposeoftherecovercommand？（）
