过去完成时：
过去完成时(The Past Perfect Tense) ：表示过去某一时间或动作以前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 。
在英语时态中，“时“指 动作 发生的时间，”态“指动作的样子和 状态 。
它表示动作发生的时间是“ 过 去的过去 ”， 侧重 事情的结果。
基本构成：
主语+had+过去分词(done)+其他成分
肯定句：主语+had+过去分词
I had arrived.
我已经到了。
He had sent the letter.
他已经寄了这封信。
否定句：主语+had+not+过去分词
However,Her father had not brought her birthday presents.
然而，她的父亲没有给她买生日礼物。
一般疑问句：Had+主语+过去分词?
肯定回答：Yes,主语+had.
否定回答：No,主 语+had not .
Had Lisa gone to costume ball ?
丽莎已经去化妆舞会了吗?
Yes,she had. 是的，她去了。
No,she hadn't. 没有，她没去。
特殊疑问句：特殊疑问词或词组+一般疑问句(Had+主语+过去分词)?
Why had The Castle become a memory of generation?
为什么电影城堡已经成为了一代的记忆?
(1)by, by the time (of), by the end of + 过去时间
(2)when. before. after…….+过去时间
(3)up till then (直到时); up until last night(直到昨晚)等。
(4)already, just, ever, yet 等。
I had finished reading the novel by nine o'clock last night.
We had learned over two thousand English words by the end of last term.
They had planted six hundred trees before last Wednesday.
当宾语从句的主句为一般过去时，且从句的动作先于主句的动作时，从句要用过去完成时。在told, said, knew, heard, thought等动词后的宾语从句。
She said that she had seen the film before.
在时间、条件、原因、方式等状语从句中，主、从句的动作发生有先后关系，动作在前的，要用过去完成时，动作在后的要用一般过去时。
When I got to the station, the train had already left.
After he had finished his homework, he went to bed.
注意：before, after 引导的时间状语从句中，由于 before 和 after 本身已表达了动作的先后关系，若主、从句表示的动作紧密相连，则主、从句都用一般过去时。如：
Where did you study before you came here?
After he closed the door, he left the classroom.
We had hoped that you would come, but you didn't.
I met Wang Tao in the street yesterday. We hadn't seen each other since he went to Beijing.
用法：
1. 过去完成时表示一个动作或状态在过去某一时间或动作之前已经完成或结束，即发生在“过去的过去”。
When I woke up, it had stopped raining.
我醒来时，雨已经停了。(主句的动作发生在“过去的过去”)
2. 过去完成时是一个相对的时态，表示的是“过去的过去”，只有和过去某一时间或某一动作相比较时才使用它。
He told me that he had written a new book.
(had written 发生在 told 之前 )
3. 过去完成时需要与一个表示过去的时间状语连用，它不能离开过去时间而独立存在。此时多与 already ， yet ， still ， just ， before ， never 等时间副词及 by ， before ， until 等引导的短语或从句连用。
Before she came to China, Grace had taught English in a middle school for about five years.
Peter had collected more than 300 Chinese stamps by the time he was ten.
4. 过去完成时表示某一动作或状态在过去某时之前已经开始，一直延续到这一过去时间，而且动作尚未结束，仍然有继续下去的可能。
By the end of last year, he had worked in the factory for twenty years. ( had worked 已有了 20 年，还有继续进行下去的可能)
If I I had taken your advice, I would have got a good grade in the exam.
如果我听取了你的建议，我将会在考试中取得好的成绩。(had taken表明过去我没有采取建议)
I expect that I had been an intern in that company.
我希望我已经是那个公司的一名实习生。(同样地，我并不是这个公司的实习生)
Honestly,if only I had studied in university.
说真的，要是我在大学学习多好!(事实上我没有，与现实相反)
I wish I had been awarded the prize in the sports meeting.
我希望我在运动会上被授予了奖励。(事实上获奖不存在)
一些引导词 since, until, no sooner...than, hardly...when, scarcely...when 等，一般可视为 "had done" 出现的信号,从句常用一般过去时。
No sooner had Whitney Houston began to sing a song than there was an instant sensation.
惠特妮·休斯顿一开始唱歌，就引起了瞬时的轰动。(注意：这里由于no sooner 否定前置，句子谓语部分倒装，所以”had”提前)
It was a long time since Darcy had lived in this city.
达西住在这座城市已经有很长时间了。(达西在过去的某个时间点之前就住在这座城市)
had planned to do(本计划做而没有做,与过去事实相反)
主句用过去完成，when/than后的从句用一般过去。为什么?
Hardly had I arrived home when it began to rain.我一到家天就开始下雨。
虽然到家的时间点和开始下雨的时间点非常接近，但是严格来说，
主句动作到家发生在从句动作下雨之前(过去的过去)，所以用had done。
注意主语主从句时态，本质上来自于现在完成三句式
只需要把主从句都提前一个时态。即把主句一般现在提前为一般过去，把现在完成和一般过去提前为过去完成。