1. Before World War II, the French regarded their Maginot Line as an impregnable bulwark against a German invasion. 第二次世界大战前，法国认为其马其诺防线是防止德军入侵无法攻破的壁垒。
2. Therefore, the family installs the company, if wants to be in an impregnable position in the intense market competition must seek some new breakthroughs. 所以，家装公司要想在激烈的市场竞争中立于不败之地必须寻求一些新的突破。
3. He lived in excessive luxury, in a palace he believed impregnable, caring little or nothing for the two and three quarter million people who occupied Primordium. 他的生活穷奢极欲，住在一座他自认为坚不可摧的宫殿中，对普利摩顿三百多万民众的死活毫不关心。
英英解释
adj.
1. able to withstand attack
2. capable of conceiving
3. incapable of being overcome, challenged or refuted
