Which four actions are possible during an Online Data file Move operation?（） [" Creating and dropping tables in the data file being moved"," Performing file shrink of the data file being moved"," Querying tables in the data file being moved"," Performing Block Media Recovery for a data block in the data file being moved"," Flashing back the database"," Executing DML statements on objects stored in the data file being moved"]
往复式压缩机连杆大头采用薄壁瓦时，检修时，一般不需要刮研，接触不良时，可稍稍拂刮。
自劳动能力鉴定结论作出2年后，工伤职工或者其近亲属、所在单位或者经办机构认为伤残情况发生变化的，可以申请劳动能力鉴定复查。
按照《社会保险法》、《建筑法》的规定，取消原规费中危险作业（），增加工伤保险费、生育保险费。 ["A.意外伤害保险费 ","B.第三者责任险 ","C.施工装备险 ","D.工程一切险"]
Your multitenant container database (CDB) contains a pluggable database, HR_PDB. The default permanent tablespace in HR_PDB is USERDATA. The container database (CDB) is open and you connect RMAN. You want to issue the following RMAN command: RMAN > BACKUP TABLESPACE hr_pdb:userdata; Which task should you perform before issuing the command?（） [" Place the root container in ARHCHIVELOG mode."," Take the user data tablespace offline."," Place the root container in the nomount stage."," Ensure that HR_PDB is open."]
反思小说大多为中篇，请简要说明原因。
