高炉下作业的调车人员配备专用对讲机，只限调车人员在炉台下与炉前工联系，机车未进入炉台下及离开出铁场后，要关闭专用对讲机。
查看答案
You executed the following command： RMAN> RECOVER COPY OF DATAFILE ’/u01/app/oracle/oradata/orcl/users01.dbf’； Which statement regarding the above command is correct？（）
A. The ’/u01/app/oracle/oradata/orcl/users01.dbf’ data file is recovered from the image copy.
B. The ’/u01/app/oracle/oradata/orcl/users01.dbf’ data file is recovered from the last incremental backup.
C. Image copies of the ’/u01/app/oracle/oradata/orcl/users01.dbf’ data file are updated with all changes up to incremental backup SC
D. Image copies of the ’/u01/app/oracle/oradata/orcl/users01.dbf’ data file are recovered using the above command if data file recovery fails.
按指标的采集来源分类，微观税收分析指标可以分为（）、（）和（）。
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