攻其不备
      Explanation: It: pronoun, refers to the enemy. When no preparedness to take advantage of the enemy attack.
      Usage: And language style; as subject, attribute; for military
      Source: Sun Tzu "Sun Tzu Posts count": "Attack is unprepared, surprise. This military commander of victory, not the first pass also."
      Examples: Common people here are factors known gentleman, it refused to ~, dark lay violent hands to take fish. ★ Qing Li Ruzhen "Flowers in the Mirror" back to the thirteenth
  • Thesaurus:  do stb.when people are off guard, to help a joint cause Wish watch, Surprise, The enemy is unprepared, Ji lei Less Their ears, sudden; as sudden as lightening; sudden peal of thunder leaves no time for covering ears