A common thing that happens when a UNIX machine is broken into is that the log files are deleted to cover the attacker's tracks.
当unix计算机受到入侵时，常见的情况是日志文件被删除，以掩盖攻击者的踪迹。
2
The reporters also cover news like a recent flood at the school caused by a broken water pipe.
记者们也采访一些新闻像最近因水管破裂而在学校引发的洪水。
3
The outcome-based control factors cover cost and yield monitoring, while behaviour-based control is broken down into the factors capabilities and activities monitoring.