我们要严防他们的破坏活动。

We should keep a sharp look-out for their disruptive activities.

当前，境内外敌对势力的渗透破坏活动加剧，反恐斗争形势严峻。

The Infiltration activities from hostile elements at home and abroad are getting increase, so the situation of anti-terrorism is grave.

个别不法分子利用网络中的一些安全漏洞进行破坏活动，由此，网络安全越来越受到人们的重视。

Vulnerabilities is used in some of the damage activities, thus, network security is more and more attention for people.