You have a computer that runs Windows 7. You manually create a system restore point. You need torestore a copy of a file stored on drive C from two days ago. You must achieve this goal in the minimumamount of time. What should you do?()
A. From Recovery, select System Restore.
B. From Backup and Restore, select Restore my files.
C. From the command prompt, run Wbadmin get items.
D. From the properties of the file, select Previous Versions.
对预抽煤层瓦斯区域防突措施进行检验时,若采用煤层残余瓦斯压力或残余瓦斯含量的直接测定值进行检验,当任何一个检验测试点的指标测定值达到或超过了有突出危险的临界值而判定为预抽防突效果无效时,则此检验测试点周围半径()内的预抽区域均判定为预抽防突效果无效,即为突出危险区域。
A. 50m
B. 100m
C. 150m
D. 120m