过去完成时有两种基本用法：“段”的用法和“点”的用法。

　　1. “段”的用法——表示一个动作或状态在过去某一时刻之前开始，一直延续到这一过去时刻，甚至还可能继续延续下去(To express duration up to or into a certain time in the past)。这种用法通常见于延续动词作谓语，且常和表示时间段的状语连用。例如：

　　She looked rather pale. She had been ill for some time.

　　When we got to the cinema, the film had been on for half an hour.

　　He said he had made great progress since he came here.

　　By the time I left the school, I had taught that class for two years.

　　Until then I had known nothing about this.

　　They had walked only a few steps when a second group of tanks drew up on the side road.

　　2. “点”的用法——表示一个动作或状态在过去某一时刻之前(已经)发生或完成(即过去之过去)。有时仅表示两个(或两个以上)动作或状态在时间上的先后关系，有时也包含前者与后者的联系或对后者的影响的意义。这种用法多见于非延续动词作谓语，且常和表示时间点的状语连用。例如：

　　When we got to the cinema, the film had already begun.

　　I was not sure whether I had met him before.

　　注意：过去完成时的“点”的用法，大多都不与表示时间段的状语连用。例如：

　　*I had opened the door for an hour before they came.

　　但有几种情况例外：

　　1) 可以和表示过去某一时刻在内的一段时间的状语连用。例如：

　　I had done my homework that morning.

　　We'd had a good harvest that year.

　　2) 某些持续性较短的动词，可以通过某种词汇手段，表示包括过去某一时刻在内的一个阶段中多次发生或反复出现的动作或状态。例如：

　　He said he had often written to her since he left Shanghai.

　　He said his friend Bob had visited him a number of times in the past two years.

　　3) 包括过去某一时刻在内的一段时间的状语还可以用于否定句中，表示一个动作或状态在一段时间内一直没有发生。例如：

　　He said he had not/never heard from her for years.

　　Up to then I had never met him.

　　综合过去完成时的两种基本用法，我们可以说，过去完成时是现在完成时或一般过去时在时间数轴上向左平移了一步(即把时间概念由以现在为时间基点推成了以过去某一时刻为时间基点)。

　　当上下文已经明确了时间的先后顺序，或表示两个(或两个以上)连贯的动作时，常可以用一般过去时来代替过去完成时。例如：

　　After/When he (had) returned from work, his wife cooked the dinner.

　　如果强调连贯动作的紧凑性，就要用一般过去时，而不用过去完成时：

　　Shortly after we joined the motorway, the car started to make a strange noise.

　　3. 过去完成时的特殊用法

　　过去完成时有时还可以用来表示在过去某一时刻之前错误的、无根据的观念、推测、想象等，或用来表示结果证明未能实现的计划、打算、愿望等。例如：

　　I had thought he was from the south until you told me.

　　I had planned/intended to attend the party last night, but someone called and I couldn't get away.

　　常见的能用于这种结构的动词有：think, suppose, expect, imagine, hope, want, intend, mean, plan 等。

　　(文/钱炳臣； 英语辅导报外研新标准高一版 04~05学年度第14期；版权归英语辅导报社所有，独家网络合作伙伴新浪教育，未经许可，不得以任何形式进行转载。)