偏航系统作用是什么？
You are working in an online transaction processing （OLTP） environment. You used the FLASHBACK TABLE command to flash back the CUSTOMERS table. Before executing the FLASHBACK TABLE command， the System Change Number （SCN） was 663571. After flashing back the CUSTOMERS table， you realize that the table is not in the correct state and the resultant changes are not what you had desired. So， you need to reverse the effects of the FLASHBACK TABLE command while ensuring that： a） No other user data in the database is affected. b） The operation takes the minimum possible time. Which option would you choose？（） ["use the ROLLBACK command with SCN 663571","perform Flashback Transaction Query with SCN 663571","execute the FLASHBACK DATABASE statement to retrieve the CUSTOMERS table as it was at SCN 663571","execute another FLASHBACK TABLE statement to retrieve the CUSTOMERS table as it was at SCN 663571"]
某男性患者，30岁，胸腹背部大面积烧伤8h。查体：BP68/sommHg，P121/min，cvp2.5mmH20，尿量15ml/h，诊断为烧伤并发休克。该患者的休克，属于（） ["感染性休克","失血性休克","创伤性休克","失液性休克","心源性休克"]
实施性施工进度计划要反映各施工作业相应的（）的安排。 ["总工期","年度内","日历天","季度内"]
At the request of a user， you issue the following command to restore a dropped table： flashback table "BIN$F2JFfMq8Q5unbC0ceE9eJg==$0" to before drop； Later， the user notifies you that the data in the table seems to be very old and out of date. What might be the problem？（） [" Because a proper range of SCNs was not specified， the wrong data was restored."," A proper range of timestamps was not specified， so the wrong data was restored."," A previous Flashback Drop operation had been performed， resulting in multiple versions of the table being stored in the Recycle Bin."," Either option A or B could be correct. Not enough information was provided to determine which."," None of the above."]
体育教学中学生产生错误动作的原因之一是教育心理因素，其主要表现在学生的（）和（）没有达到相应的水平等。
