今天荣老师分享过去完成时的用法。
一、定义
过去完成时是谈论在过去的另一个动作之前完成的动作。
换句话说，它用来描述发生在过去的另一个事件之前的事件。
过去完成时不是用来描述过去的特定时间，而是用来显示事件的顺序。
Before I went to bed, I had brushed my teeth.
在我上床睡觉之前，我刷了牙。
"刷牙"是在"上床睡觉"之前;
“上床睡觉”用的是过去时went to bed;
所以“刷牙”就用过去完成时had brushed.
By the time I got to the party, everyone had left.
我到聚会的时候，大家都走了。
"大家都走了"是在"我到达聚会之前";
“到达聚会”用的是过去时got to the party;
所以“都走了”用的是过去完成时had left.
She had already seen the movie, so she didn’t want to watch it again.
她已经看过那部电影了，所以她不想再看一遍。
“她已经看过那部电影”是在“不想再看一遍“之前;
“不想再看一遍”用的是过去时didn't want to watch;
所以“她已经看过那部电影”用的是过去完成时had seen.
过去完成时也可以用在间接引语中，用来描述在报告时间之前所说或所做的事情。
She told me that she had finished her homework.
她告诉我她已经完成了作业。
二、用法
1. 用来描述在过去发生的另一个动作之前完成的动作
By the time I arrived at the party, the guests had already eaten all the food.
当我到达聚会的时候，客人们已经吃光了所有的食物。
She had finished her homework before she went to bed.
她在睡觉前完成了家庭作业。
2. 描述发生在过去另一个动作之前的一段时间
They had been married for ten years before they decided to have children.
他们结婚十年才决定要孩子。
He had lived in New York City for five years before he moved to Los Angeles.
他搬到洛杉矶之前在纽约住了五年。
3. 描述过去期望发生但没有发生的动作
I had hoped to see the movie, but it was sold out.
我本来希望看这部电影的，但是电影票已经卖完了。
She had planned to go to the concert, but she got sick.
她本来打算去听音乐会的，但她病了。
下图总结了过去完成时的用法及例句。
参考来源：
https://www.engclub.in/p/past-perfect-tense.html
https://eslbuzz.com/past-perfect-tense/
