1．构成：had + 过去分词
2．功能：
（1）表示过去某个动作或某个具体时间之前已经发生、完成的动作。“过去的过去”。
They had got everything ready before I came.
The play had begun before I got to the theater with my boyfriend.
（2）过去完成时常用于 hardly / scarcely ... when, no sooner ... than等固定句型结构中。（此乃超级重点句型，意为：“一……就”）
She had hardly / scarcely gone to bed when the bell rang.
No sooner had he arrived at the railway station than he met her parents.（注意 no sooner 在句首时句型倒装。）
（3）intend（打算），mean（意味），hope（希望），want（想要），plan（计划）等动词的过去完成时用来表示本打算做而没有做的事。
I had intended to call on you yesterday, but someone came to see me just when I was about to leave.
（……原想昨天去看你……）
They had planed to hold a football match last week, but they had to cancel it because the bad weather.
（……原计划上周举行一场足球赛……）
