语法点：过去完成时 (Past Perfect)
过去完成时表示“过去的过去”：在过去某个时间或动作之前已经完成的动作。它总是需要一个过去的参照点，这个参照点常由 after / before / when 引导的从句或上下文中的一般过去时给出。本课作者“吃完午饭之后”才找包、包“早已被狗叼走”，这些比“找包”更早发生的动作都用过去完成时。判断时先找出两个过去动作，较早的那个用 had + 过去分词。
结构
| 形式 | 例句 |
|---|---|
| 肯定 | I had left it on a chair. / My dog had taken it. |
| 否定 | I had not (hadn't) left it on a chair. |
| 一般疑问 | Had you left it on a chair? — Yes, I had. / No, I hadn't. |
| 特殊疑问 | Where had you left it? |
| 常见搭配 | After I had had lunch, I looked for my bag.（after + 过去完成时，主句一般过去时） |
课文中的例句
- [句 1] After I had had lunch at a village pub, I looked for my bag. — after 从句用过去完成时，“吃午饭”先于“找包”；第一个 had 是助动词，第二个 had 是 have 的过去分词。
- [句 2] I had left it on a chair beside the door and now it wasn't there! — “把包放在椅子上”发生在“发现它不见了”之前。
- [句 9] 'My dog had taken it into the garden. He often does this!' — 狗叼走包发生在店主出去找之前，是“过去的过去”。
- [句 3] As I was looking for it, the landlord came in. — 对比：同时发生的两个过去动作用过去进行时 + 一般过去时，而不是过去完成时。
补充例句
- When I got to the pub, the landlord had already gone out. 我到酒馆时，店主已经出去了。
- She couldn't pay the bill because she had left her bag at home. 她付不了账，因为她把包忘在家里了。
- After the dog had taken the bag into the garden, it came back to the door. 狗把包叼进花园后，又回到了门口。
易错点
- ❌ After I had lunch, I had looked for my bag. → ✅ After I had had lunch, I looked for my bag. 先发生的动作（吃饭）用过去完成时，后发生的（找包）用一般过去时，不要颠倒。
- ❌ I had leave it on a chair. → ✅ I had left it on a chair. had 后必须接过去分词，不是动词原形。
- ❌ My dog has taken it into the garden.（叙述过去的事） → ✅ My dog had taken it into the garden. 参照点在过去，要用 had，不用 has。
- ❌ Yesterday I had gone to a pub. → ✅ Yesterday I went to a pub. 只有一个过去动作、没有“更早”的参照时，用一般过去时即可。