23考研英语备考 | 必备基础语法(27)-过去完成时

一、构成

Structure

过去完成时由“助动词had+动词的过去分词”构成。

二、基本用法

Application

(1)过去完成时表示过去某一时间前就已经发生或完成了的动作。过去完成时的时间状语有by(yesterday)，by then，by the end of(last...)或者由when，before等引出状语从句。有时句子中会有already，just，once，ever，never等词，也会有for...或since...构成的时间状语。如:

They had already finished cleaning the classroom when their teacher came. 

当老师来的时候他们已经打扫完了教室。

The woman had left before he realized she was a cheat.

在他发觉那个妇女是个骗子时她已经走掉了。

(2)过去完成时常用于宾语从句中，after引导的从句中，或者从句是before引导的主句中。如:

After I had put on my shoes and hat, I walked into the darkness.

我穿上鞋子戴上帽子走进了黑暗之中。

He said that he had never seen a kangaroo before.

他说他以前从来没有见过袋鼠。