Which three tasks can be performed using a duplicate database? (Choose three.)
A. Testing the backup and recovery procedures
B. Testing the upgrade of an Oracle database to a new release
C. Testing the effect of an application changes on database performance
D. Continuously updating archive log files from the target database to support failover
此题考点是复制数据库的目的：
1.测试备份和恢复过程
2.测试数据库升级到新版本
3.测试应用程序对数据库上的性能的影响
4.创建一个备份数据库（DG 配置）
5.生成报表
D 错误，如果没配置成 DG 配置，是无法连续的从目标库更新归档，达到支持故障转移的目的的。