过去完成进行时
Past Perfect Continuous
过去完成进行时描述过去某个时刻或动作之前持续了一段时间的动作。由 had been + 动词-ing 构成，强调先前持续动作的时长。
何时使用
用于强调某个动作在过去某一时刻之前已经持续了多长时间。也可用来解释某个过去情况的原因。
结构
S + had been + V-ingShe had been studying for three hours before the exam.
她在考试前**已经学**了三个小时。
S + hadn't been + V-ingThey hadn't been waiting long when the bus arrived.
公交车到的时候，他们还**没等**多久。
Had + S + been + V-ing?Had you been working there long before you quit?
你辞职之前**在**那里**工作**了很久吗？
信号词
- for
- since
- before
- until
- all day
- how long
例句
He had been driving for six hours when he finally stopped.
他**开**了六个小时的车，最后终于停了下来。
I had been waiting for an hour before she arrived.
她到之前，我**已经等**了一个小时。
They were exhausted because they had been running.
他们很累，因为**一直在跑**。
She had been learning French for years before she moved to Paris.
她搬到巴黎之前**学**了多年法语。
Had it been raining when you left?
你离开的时候**在下雨**吗？
拼写规则（第三人称单数）
| 大多数动词 | 加 -ing | wait → waiting, run → running |
|---|---|---|
| 以不发音的 -e 结尾 | 去 -e 加 -ing | drive → driving, write → writing |
| 以辅音-元音-辅音结尾的短动词 | 末尾辅音双写 + -ing | sit → sitting, swim → swimming |
常见错误
I had waited for an hour before she arrived.
I had been waiting for an hour before she arrived.
要强调过去某个时点之前持续动作的时长，用过去完成进行时（had been + V-ing），而不是过去完成时（had + V3）。
She had been knowing him for years before they married.
She had known him for years before they married.
状态动词不用进行形式 —— 改用过去完成时。
提示
把它想成"过去的过去 + 持续时长"。如果过去完成时（had done）="在那之前"，那么过去完成进行时（had been doing）="在那之前一段时间就一直在做"。进行形的部分 = 持续时长。