过去完成时：记住五个字“过去的过去”，had+过去分词，先发生用had done后发生用did
引言
过去完成时是八大时态里最容易被绕晕的一个。记住五个字就够：过去的过去。
核心概念：过去的过去
```text
两个动作都发生在过去，并且有先后顺序：
先发生的动作 → 过去完成时（had + 过去分词）
后发生的动作 → 一般过去时（did）
```
```text
The train had left when I got to the station.
火车先开走（had left），我后到站（got）
→ 先发生用 had left，后发生用 got
```
结构：不管第几人称，统一用 had
```text
主语 + had + 过去分词
I had finished my homework before 10 o'clock last night.
She had already gone when I arrived.
They had seen the film twice.
```
```text
had 不随人称变化：I/he/she/they 都用 had
```
时间轴看先后
```text
过去 现在
│ │
│ ①先发生：had done
│ │
│ ②后发生：did
│
过去的过去 过去 现在
```
```text
我到家前，妈妈已经吃完晚饭了。
Mom had finished dinner before I got home.
（finish 在先 → had finished；get home 在后 → got）
```
八大时态顺口溜（速记）
```text
一般现在时 动词用原形
一般过去时 动词过去式
一般将来时 will 加原形
现在进行时 am/is/are 连 ing
过去进行时 was/were 连 ing
现在完成时 have/has 加分词
过去完成时 had 后面跟分词
过去将来时 would 后面跟原形
```
实战练习
```text
- 昨晚十点前我已经完成作业了。
I ______ (finish) my homework before ten o'clock last night.
→ had finished（过去十点之前，先发生）
- 火车开走后，我才到车站。
The train ______ (leave) when I got to the station.
→ had left（先离开，后到达）
- 她到的时候，我已经走了。
She ______ (arrive) after I had gone.
→ arrived（后发生 → 一般过去时）
```
总结
```text
过去完成时 = 过去的过去
结构：had + 过去分词（所有人称不变）
先发生 → had done；后发生 → did
```
```text
今日小抄：
The train had left when I got to the station.
Mom had finished dinner before I got home.
```