单项选择题 Your database is running in the ARCHIVELOG mode. You placed a tablespace， tbs_1， offline with the immediate option. Which statement is correct in this scenario？ （）

多项选择题 The following are the details of your database：Instance name：test  Host name ： tech1.us.oracle.com IP address：145.33.230.186 Enterprise Manager Console HTTP Port number：5500  You started the database instance and you want to manage your database remotely with Enterprise Manager through a Web browser.  Which two URLs would you use to access the Database Control？（）

单项选择题 You find today’s performance of your production database to be the best ever.  Therefore， you want to be notified in the future whenever the performance degrades by 10% of today’s performance. What is the first step that you would take to ensure this？（）