过去完成时

过去完成时(The Past Perfect Tense)：表示过去某一时间前就已经发生或完成了的动作，对过去的某一点造成的某种影响或是结果，用来指在另一个过去行动之前就已经完成了的事件。

过去完成时

• 构成
  • 肯定：had +done
  • 否定：had+ not+ done
  • 疑问：Had +主语+done？
• 标志词
  • by the end of + 过去时间
  • by the time + 从句
• 用法
  • 表示过去过去某个时间之前已经完成的动作
  • 过去完成时的动作发生在“过去的过去“
• 例句
  • Laura said she had been a teacher before she married.
  • By the end of last month we had learned 2 Units..
  • She had left by the time I arrived.
• 主要用于从句中
  • 状语从句
    • When he got to the airport, the flight had taken off.
    • She didn’t go to bed until she had finished the work.
  • 宾语从句
    • He told me he had finished all the work.
    • She said (that)she had never been to Paris
• 比较
  • 一般过去时
    • I lost my new book.
      • 强调动作发生在过去某一时间
    • I went to the park last week.
  • 过去完成时
    • He said that he had met her before.
      • 强调过去某一时间以前发生的动作(即过去的过去)
    • She told us that she had visited the park before,.
• 这种时态从来不孤立使用句中有明显的参照动作或时间状语