Which three statements are true about Flashback Database?（） [" Flashback logs are written sequentially, and are archived."," Flashback Database uses a restored control file to recover a database."," The Oracle database automatically creates, deletes, and resides flashback logs in the Fast RecoveryArea."," Flashback Database can recover a database to the state that it was in before a reset logs operation."," Flashback Database can recover a data file that was dropped during the span of time of the flashback."," Flashback logs are used to restore to the blocks' before images, and then the redo data may be used to roll forward to the desired flashback time."]
简要叙述市场法的优点。
黄某，男性，32岁，头部被铁棍击伤，头皮裂开已12h以上，伤口无明显感染，其处理为（） ["凡士林纱布覆盖","彻底清创，一期缝合","C，清创并置放胶片引流","观察2一3d，二期缝合","不予缝合，以免增加损伤"]
水泥强度等级是根据胶砂法测定水泥（）的抗压强度和抗折强度来判定。 ["3日和7日","3日和28日","7日和14日","7日和28日"]
把吃作为小说主要内容与线索的小说有陆文夫的《美食家》和（） ["邓友梅的《那五》","冯骥才的《神鞭》","刘绍棠的《蒲柳人家》","林斤澜的《溪鳗》"]
如何防止泵的振动？
