文档介绍：过去完成进行时 Past Perfect Continous tense
.
1
定义：
通常表示某个过去正在进行的动作或状态，持续到过去某个时刻，还未完成，一直持续到之后的当前才结束
过去完成进行时结构：
主语 +had+been +doing （have/has随人称的变化而变化）
eg:I had been looking for the book for days before I found it.
这本书我找了好多天才找着的。
.
2
过去完成进行时用法
①表示过去某一时间之前一直进行的动作。
过去完成进行时表示动作在过去某一时间之前开始，一直延续到这一过去时间。和过去完成时一样，过去完成进行时也必须以一过去时间为前提。
I had been looking for it for days before I found it.
这东西我找了好多天才找着的。
They had only been waiting for the bus a few moments when it came.
他们只等了一会儿车就来了。
.
3
②表示反复的动作。
He had been mentioning your name to me.
他过去多次向我提到过你的名字。
You had been giving me everything.
你对我真是有求必应。
.
4
③过去完成进行时还可用在said，supposed等引起的间接引语中，代替现在完成进行时：
eg:
He said，“I have been speaking to John．”(直接引语)
= He said that he had been speaking to John．（间接引语）
He thought，“She was watching me when I passed．”（直接引语）
= He thought that she had been watching him when he had passed.
（间接引语）
.
5
④过去完成进行时之后也可接具有“突然”之意的when分句。
I had only been reading a few minutes when he came in.
我刚看了几分钟他就进来了。
She'd only been reviewing her lessons for a short while when her little sister interrupted her.
她温****功课才一会儿，她妹妹就打断她了。
I had been sleeping when my friend telephone me.
我正在睡觉时，我的朋友给我打电话。
.
6
①肯定句：主语+had+been+v-ing+其他.
eg: My mother has been teaching English for twenty years．
②否定句：主语+had+not+been+v-ing+其他.
eg: She had not been studying abroad for years since she came back
注：这种时态很少用在否定句中，而多以过去完成时代替：
He had not practiced English for many years．（普通说法）
He had not been practicing English for many years．（少见）
.
7
③一般疑问句：Had+主语+过去分词+其他?
eg:Had they been expecting the news for some time?
肯定回答：Yes,主语+had.
否定回答：No,主语+had not .
.
8
④特殊疑问句：特殊疑问词或词组+had+主语+过去分词+其他?
eg:What had they been doing for a while when you arrived?
.
9
过去完成进行时语法含义：
1）尚未完成： He had been writing the novel．
（He had not finished it yet．）
2）企图： He had been studying the meaning of this proverb．
（He was trying to study it．）
3）未得结果： We had been studying what our enemy had said．
(But we were n