The town walls were built as a defence against enemy attacks.

城墙是为防御敌人袭击而修建的。

《牛津词典》

Residents have the responsibility of being the first line of defence against wildfires.

居民有责任成为野火的首要防卫人员。

《柯林斯英汉双解大词典》

Despite anything the science of medicine may have achieved, the immune system is our main defence against disease.

不管医疗科学已取得了什么样的进步，免疫系统仍是我们抵抗疾病的主要防御手段。

《柯林斯英汉双解大词典》

This should help to unlock cross-holdings of shares and remove a key defence against hostile takeovers.

ECONOMIST: Stumbling yet again?

America wants to bin the ABM treaty because it prevents it building a defence against missiles.

ECONOMIST: A running feud

In the end, the best defence against corruption is the vigilance of activists like Mr Saldi.

ECONOMIST: Pervasive corruption is bad for business