固若金汤的英文：
[Literal Meaning]
solid/like/metal/boiling water
a city with walls made with metal and a moat of boiling water

[解释]
形容工事非常坚固。

[Explanation]
strongly fortified and impregnable

[例子]
这座城固若金汤，再有一倍的敌人也攻不进来。

[Example]
The city is impregnable and even double number of enemies would not intrude into it.

Immune to attack;impregnable.
固若金汤攻不破的;固若金汤的

an impregnable fortress.
固若金汤的堡垒

Our psychological defence is far from impenetrable.
我们国家人民的心理防卫就谈不上固若金汤了。

The old Dutch fort with its thick high walls looks virtually impregnable.
古老的荷兰城堡城墙又厚又高，看起来几乎固若金汤。