impregnable [ɪmˈprɛɡnəbəl]

例句:

• The Bundesbank's seemingly impregnable position has begun to weaken.
  德意志联邦银行看似不可撼动的地位开始削弱了。
  
• She carries within an impregnable conviction of being lovable.
  来自A. Storr
• 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。
  
• In those impregnable mountains, the guerrillas could hold out for years.
  在那些易守难攻的大山里，游击队可以坚持很多年。
  
• Military experts believe the islands are now virtually impregnable.
  来自BBC
• "Vettel must be feeling impregnable," says Edwards.
  来自BBC