罗马军团击退外侮，但却只是初尝外患滋味，罗马从今以后都必须小心提防。

The Roman Legions chased them back but it was only a taste of what was to come. Rome was now, and forever after looking over her shoulder.

为蚂蚁提供这种住宿环境对树也有好处，因为蚂蚁会为其房东提供非常重要的服务：守卫树木，抵抗外侮。

Producing this accommodation also benefits the tree, for the ants provide their landlord with a valuable service: they guard it against its enemies.