catch someone out 
phrasal verb with catch verb uk/kætʃ/ us/kætʃ/ caught | caught
  informal 
  (SHOW WRONG)      
  指出…的过失
to show that someone is doing wrong
  I suspected he wasn't telling me the truth, and one day I caught him out when I found some letters he'd written. 我怀疑他没有告诉我实情,有一天,我发现了他写的一些信后戳穿了他。 
   (TRICK)      
  耍花招使…出错;诱骗…犯错误
to trick someone into making a mistake
  The examiner will try to catch you out, so stay calm and think carefully before you speak. 考官会诱导你犯错,所以你要沉着冷静,三思而后言。 
   (CAUSE DIFFICULTY)      
 置…于困境
to put someone in a difficult situation
  A lot of people were caught out by the sudden change in the weather. 许多人都被这突如其来的天气变化弄得很狼狈。