double agent

例句：

1. 1. He was a double agent during World War II.
   他在第二次世界大战期间是一名双重间谍。
2. 2. The double agent betrayed his country to the enemy.
   这名双重间谍背叛了他的国家给敌人。
3. 3. The double agent was able to gather crucial information from both sides.
   这名双重间谍能够从双方收集到关键信息。