引种时,种猪运回场后,要隔离()天,进行疫病检测和补打疫苗后,方可转入猪群。
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You are performing flashback of the ORDERS table in the Scott’s schema because some important data is deleted in the table by mistake. The SCN number was 771513 at the time of deletion. You issued the following statement to perform Flashback Table: SQL> FLASHBACK TABLE ORDERS TO SCN 771513; What is the prerequisite to perform Flashback Table?()
A. You must configure OMF in your database.
B. You must enable block change tracking feature in your database.
C. You must enable ROW MOVEMENT feature on the ORDERS table.
D. You must use the Flashback Version Query before using the Flashback Table feature.
下述关于缓燃期的论述中错误的是()。
A. 缓燃期内由于燃烧速度缓慢,而使大量空气过剩
B. 缓燃期内缸内温度上升到最高循环温度
C. 缓燃期为可控燃烧阶段
D. 从放热规律观点此阶段称扩散燃烧阶段
退役的军马、军犬使用铁路运输时,属于装备物资铁路军事运输。
A. 正确
B. 错误