(1) hardly...when, scarcely...when, no sooner...than, barely...when均可表示一件事情在另一件事情发生后很快发生。主句中通常用过去完成时，从句中用过去时。

• I had hardly/scarcely/barely closed my eyes when the telephone rang.
  我刚一闭眼，电话就响了。
• We had barely arrived when we received the order to start.
  我们刚刚到达就又接到出发的命令。
• I had no sooner closed the door than he started knocking on it.
  我刚关上门他就开始敲门了。

 (2) 当hardly, scarcely, barely, no sooner放在句首时，句子应倒装。

• Hardly had I arrived when I had a new problem to cope with.
  我刚到达，就遇到一个新问题要解决。
• Scarcely had we started lunch when the doorbell rang.
  我们刚开始吃午饭，门铃就响了。
• No sooner had she closed her eyes than the man started knocking at the door.
  她刚合上眼，这人就开始敲门了。