过去完成时态的用法？
什么是过去完成时?顾名思义，过去完成时代表着在过去的某个时间或动作之前已经完成的动作，也就是说，如果一个动作发生在过去的过去，我们就可以用过去完成时。下面我就讲讲过去完成时的用法。
一、过去完成时的用法
1. 过去完成时表示在过去某一时间或动作以前已经完成了的动作。这个过去的时间常用by，before等介词短语或一个时间状语从句表示，也可以暗含在上下文中。
I had finished my homework before supper.我在晚饭前就把作业做完了。
The play had already started when we got to the theatre. 我们到剧场时戏已经开始了。
By the end of June they had treated over 10,000 patients. 到六月底他们已经治疗了一万多病人。
2. 过去完成时还可表示过去某一时刻之前发生的动作或状态持续到过去某个时间或还要持续下去，常与for，since等词连用。如：
He had served in the army for ten years before he retired last year. 他在部队干了十年，去年退役了。
He told me that he had known her since he was a child. 他告诉我他从小就认识她。
He had learned English for eight years before he went to England for further study. 他在去英国深造前，已学了八年英语。
3. 在一段情景连贯的文字中，先发生的事放在后面叙述时，要用过去完成时。如：
Tom flew home, but his father had already died. 汤姆乘飞机回家，他的父亲却已经去世了。
4. 过去完成时也用于hardly...when..., no sooner...than..., It was the first time + that分句等一些固定句型中。
He had no sooner left the room than they began to talk about him. 他刚离开房间，他们就议论起他来。
We had hardly begun when we were told to stop.
我们刚开始就被叫停。
It was the first time that he had ever spoken to me in such a tune.他用这样的语调跟我讲话，这是第一次。
二、过去完成时与一般过去时的比较
1. 当一个由before, after, as soon as 等连词引导的从句所表示的动作和主句的动作紧接着发生时，两个动作均可用一般过去时来表示。
We had breakfast after we did morning exercises.
做完早操后，我们吃早饭。
The train started to move just before he reached the platform. 他到月台时火车刚开走。
They started ploughing as soon as they got to the fields. 他们一到地里就开始耕地。
2. 按时间顺序叙述两个或两个以上接连发生的动作时，用一般过去时。
He entered the room, turned on the light and sat down at the table. 他走进屋子，开启灯，坐在桌子旁。
3. 在表示某人过去未曾完成的“心愿”、“打算”、“计划”、“想法”、“许诺”等时，hope, mean, plan, think, intend等谓语动词常用过去完成时。
I had hoped to be back last night, but I didn’t catch the train. 我本来希望昨晚回来的，但没搭上火车。
We had thought to return early but they wouldn’t let us go. 我们本想早回来的，但他们不让我们走。
4. 在表示过去的句子中出现常与完成时态连用的词，如：already，yet，since，for，ever，never及次数名词等时，常用过去完成时来表示。
When we got there the basketball match had already started. 我们到那里时，篮球赛已经开始了。
The old man said that he wanted to go where he had never been. 老人说他想到他从未去过的地方去。
5. 如果句中出现了表示具体的过去时间的状语，句子的内容为过去的实际情况或句子的内容为历史事实时，句中的动词时态常用一般过去时。如：
The teacher said that it was Columbus who first discovered the American continent.老师说是哥伦布最早发现了美洲大陆。
6. 表述说话人始料未及的事情时，句子的谓语动词常用一般过去时。由于受汉语表述习惯的影响，常会用错时态。
Jack, you are also here! I didn’t see you. 杰克，你也在这啊!我没有看见你。
