在中性点不接地系统中，只有两条线路长度相等的线路，其中一条线路发生单相接地，则在故障线路的首端零序电流互感器测得的零序电流为（）。 两回线零序电流值之和。 零。 故障线路本身的零序电流值。
In which scenario is a Database Administrator NOT required to perform an incomplete recovery？（） when all the online redo log groups are multiplexed and one of the members of a group is missing。 when all the online redo log groups are not multiplexed and one log group is missing。 when all the control files are missing。 when some important tables are deleted from the database and purged from the Recycle Bi。
钻头主切削刃上各点的后角大小（）。
标准煤的发热量为（）。 20934KJ。 25120.8KJ。 29307.6KJ。
On Friday at 11:30 am you decided to flash back the database because of a user error that occurred at 8:30am. Which option must you use to check whether a flashback operation can recover the database to the specified time?（） Check the alert log file。 Query the V$FLASHBACK_DATABASE_LOG view。 Query the V$RECOVERY_FILE_DEST_SIZE view。 Query the V$FLASHBACK_DATABASE_STAT view。 Check the value assigned for the UNDO_RETENTION parameter。
管理过程由哪些环节构成（）
