Changefulness and the complexity of network environment, as well as the frailty of information system, have decided the objective existence of network safe threat.
网络环境的复杂性、多变性，以及信息系统的脆弱性，决定了网络安全威胁的客观存在。
Well I think that we should always call matter 'time matter' or matter of time so that we never for a moment forget its essential temporality and essential changefulness.
