过去完成时
过去完成时的意思
表示在过去某个时间或某个动作之前发生的动作，表示一个动作或状况在某一时间或动作之前已经完成，其动作发生的时间是过去的过去，它的参照物是一般过去时。
过去完成时的标志
特定的时间状语
①by+过去的时间点
He had finished reading the book by 10 oclock yesterday.
到昨天10点前，他已经读完了这本书。
②by the end of + 过去的时间点
We had learned a lot of English songs by the end of last term.
到上学期末大家已经学了不少英文歌曲。
③由by the time, before, when等引导时间状语从句时，主从句的动作发生有先后，动作在前的用过去完成完成时。
By the time I went outside, they had already left.
当我出去时。他们已经离开了。
The train had already left when I got to the station.
我到达车站时火车已经离开了。
具体的语境
①主句为一般过去时，且宾语从句的动作先于主句的动作发生时，从句要用过去完成时。
She said that she had seen the film before.
她说她以前已经看过这部电影了。
②上下文语境
I met Jim in the street yesterday. We hadnt seen each other since he went to Beijing.
我昨天在街上碰见吉姆了。自从他去北京后，大家就再没见过面。
经典例题
例1. When she got to the station, the bus_______ the station for ten minutes.
has left B. had left
had been away from D. left
答案：C
例2. The meeting _______ by the time I got there yesterday.
was on B. has been on
had begun D. has begun
答案：C
例3. By the end of last month, I ________ all the CDs of Zhou Bichang.
collect B. collected
have collected D. had collected
答案：D
