（30）Which two statements are true with respect to the maintenance window?(Choose two)

A. A DBA can enable or disable an individual task in all maintenance windows.

B. A DBA cannot change the duration of the maintenance window after it is created.

C. In case of a long maintenance window,all Automated Maintenance Tasks are restarted every four hours.

D. A DBA can control the percentage of the resource allocated to the Automated Maintenance Tasks in each window.

答案：（A、D）