A. If the lost redo log group is ACTIVE,you should first attempt to clear the log file.
B. If the lost redo log group is CURRENT,you must clear the log file.
C. If the lost redo log group is ACTIVE,you must restore,perform cancel-based incomplete recovery,and open the database using the RESETLOGS option.
D. If the lost redo log group is CURRENT,you must restore,perform cancel-based incomplete recovery, and open the database using the RESETLOGS option.
答案：（D）
解析：
C（X），首先要执行ALTER SYSTEM CHECKPOINT，根据该命令是否成功,来决定是否需要进行不完全恢复
即不一定非得执行不完全恢复