Anti-virus programs are necessary but don’t always guard against intrusions.

反病毒程序是有必要用的但是仍不能够经常的阻止渗透。

youdao

In China Germany France Russia Singapore Italy and the United States you are trying to ward off the virus of liberty by erecting guard posts at the frontiers of Cyberspace.

在中国、德国、法国、俄罗斯、新加坡、意大利和美国你们试图通过在赛柏空间的边疆设立岗哨把自由的病毒挡在门外。

youdao

In China, Germany, France, Russia, Singapore, Italy and the United States, you are trying to ward off the virus of liberty by erecting guard posts at the frontiers of Cyberspace.

在中国、德国、法国、俄罗斯、新加坡、意大利和美国，你们试图通过在赛柏空间的边疆设立岗哨，把自由的病毒挡在门外。

youdao

She says people must keep up their guard against the virus, which is unpredictable and could change into a far more dangerous form.

VOA: standard.2009.12.29

But she warned members of the public to be on their guard against the virus.

BBC: Flu rate 'at record low'