过去完成时的谓语动词由“had”和过去分词构成，用于表示在过去某个时间之前已完成的动作。无论主语是单数还是复数，都只需在“had”后添加过去分词。例如，“had eaten”，“had written”，“had spoken”等。掌握这种构成方式有助于更好地理解和使用英语语法。
例如，我们可以说：“By the time I arrived at the party, the cake had already been eaten.” 在这个例子中，“had eaten”就是过去完成时的谓语动词。
要构成过去完成时的谓语动词，首先需要使用助动词“had”，然后根据动词的不同形式使用相应的过去分词。下面是一些常见动词的过去完成时构成：
- eat - had eaten
- write - had written
- speak - had spoken
- go - had gone
- see - had seen
- do - had done
- be - had been
- have - had had
需要注意的是，在构成过去完成时的谓语动词时，不管主语是单数还是复数，都只需要在助动词“had”后添加过去分词即可。例如，“They had eaten dinner before the movie started.” 和 “He had eaten dinner before the movie started.” 都是正确的。
