英语四级考试中，单独考察的题几乎没有，但是语法知识点却贯穿整张试卷，下面是频道为大家整理的知识，希望可以为大家带来帮助，一起来学习一下吧。 　　过去完成时 　　1) 概念：表示过去的过去 　　其构成是had 过去分词构成。 　　那时以前 那时现在 　　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……