英语过去完成时的构成和用法

过去完成时是指过去的某一事件或某一动作之前发生的事情或完成的动作或存在的状态，俗称“过去的过去”一般由助动词had+动词的过去分词构成

其否定句就是直接在had后+not，疑问句即提前had到句首

例：

1.When I got there，the boy had left. 当我来到那时，那个男孩已经走了。

2.She told me she hadn't have breakfast. 她告诉我她没吃晚饭。

3.Have you known anything about our school before you came here？你来我们学校之前就了解我们学校了吗？

had 过去分词 表达过去的过去， 动作在过去某一时间之前已经发生或完成，

宾语从句，时间壮语从句， by the end of last year/ term

He said that he had read this book.

We had learned more than 4000 words by the end of last month.

They had left when I arrived.

The teacher had telephoned my mother before I told her.