pluperfect

例句：

1. 1. I had finished my homework by 7 o'clock last night.
   我昨晚七点之前完成了我的作业。
2. 2. He said he would come to the party, but he didn't show up until nine o'clock.
   他说他会来参加聚会，但他直到九点才出现。
3. 3. She asked me if I had seen her sister before she left for the trip.
   她问我在她还去旅行之前是否见过她的妹妹。