过去完成时(Past Perfect Tense)是英语中的一种时态,表示在过去某一时间点之前已经完成的动作或状态。它的构成由“had + 过去分词”组成。
例如:
我在看电影之前已经吃过晚饭了。
I had already eaten dinner before I watched the movie.他们到达机场时,飞机已经起飞了。
When they arrived at the airport, the plane had already taken off.她发现自己把钱包落在家里了,但是已经迟到了。
She realized she had left her wallet at home, but she was already late.
在上述例句中,“had”是助动词,用来表示过去完成时。过去分词可以是动词的第三形式,也可以是由“be”动词加上现在分词构成的复合形式。
例如:
我们已经完成了这项任务。
We had completed the task.她已经睡了十个小时了。
She had been sleeping for ten hours.
需要注意的是,过去完成时常常与过去时连用,表示在过去某一时间之前的动作或状态已经完成,而且对现在或过去发生的事情产生了影响。
例如:
我以前住过法国,所以我会说一些法语。
I had lived in France before, so I can speak some French.她已经去过那个城市,所以她知道那里的情况。
She had been to that city before, so she knew about it.
过去完成时的使用可以让我们更加清晰地表达过去发生的事情,帮助我们更好地理解英语语法的规则和用法。