2020湖南普通专升本英语语法：过去完成时的用法

专升本英语语法：过去完成时的用法
1）概念：表示过去的过去，其构成是had+过去分词构成。
2）用法
a.在told,said,knew,heard,thought等动词后的宾语从句。
She said(that)she had never been to Paris.
b.状语从句
在过去不同时间发生的两个动作中，发生在先，用过去完成时；发生在后，用一般过去时。
When the police arrived,the thieves had run away.
c.表示意向的动词，如hope,wish,expect,think,intend,mean,suppose等，用过去完成时表示"原本…，未能…"
We had hoped that you would come,but you didn't.
3)过去完成时的时间状语before,by,until,when,after,once,as soon as。
He said that he had learned some English before.
By the time he was twelve,Edison had began to make a living by himself.
Tom was disappointed that most of the guests had left when he arrived at the party.
典型例题
The students ___ busily when Miss Brown went to get a book she ___ in the office.
A.had written,left B，were writing,has left C.had written,had left D.were writing,had left
答案D."把书忘在办公室"发生在"去取书"这一过去的动作之前，因此"忘了书"这一动作发生在过去的过去，用过去完成时。句中when表示的是时间的一点，表示在"同学们正忙于……"这一背景下，when所引导的动作发生。因此前一句应用过去进行时。
注意：
had no…when还没等……就……
had no sooner…than刚……就……
He had no sooner bought the car than he sold it.