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》

This wall is a defence against the sea.

这堵墙是抵挡海水的。

youdao

The forest will act as a defence against desert dust.

森林能起到防御沙漠尘土的作用。

youdao

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

ECONOMIST: A running feud

This could provide a defence against future emissions regulations or perhaps help it grab green subsidies.

ECONOMIST: Schumpeter: Why firms go green | The

He is seeking a court declaration that any doctor who killed him would have a defence against such a charge.

BBC: Right to die: Paul Lamb takes up Tony Nicklinson fight