英语基础语法：过去完成时
一、构成方法
由 had 加动词的过去分词构成.
二、用法说明
■表示在过去某一时刻或某一动作之前已经完成了的动作,即“过去的过去”.如：
She said she had never been to Paris.她说她从未去过巴黎.
When the police arrived,the thieves had run away.警察到达时,小偷们早就跑了.
By the time he was twelve,Edison had begun to make a living by himself.到了十二岁那年,爱迪生开始自己谋生.
注意：过去完成时是一种相对时态,一定要有一个作参照的过去时间或过去动作作比较,否则,就不能用过去完成时.但下列3种情况虽然有是先后发生的两个过去动词,却同用一般过去时：
1.先后发生的一系列动作,但并不强调先后时,最后两个动词用then,and,but 等连接.如：
On Saturday afternoon,Mrs Green went to the market,bought some bananas and visited her cousin.星期下午,格林夫人去了市场,买了些香蕉,然后去看望了她的表姐.
2.两个动作是紧接着发生的,可用一般过去时.如：
When I heard the news,I was very excited.我听到那个消息时,非常高兴.
3.叙述历史事实,可用一般过去时.如：
Our teacher told us that Columbus discovered America in 1492.我们老师告诉我们哥伦布于1492年发现了美洲.
■表示从过去某一时刻开始一直延续到另一过去时刻的动作或状态.跟现在完成时一样,也常与 how long,for three days,before 等表示一段时间的状语连用.如：
When Jack arrived he learned Mary had been away for almost an hour.当杰克到来时,他才了解到玛丽已经离开差不多一个小时了.
■表示未曾实现的希望或打算.表示希望或打算的动词,如hope,want,expect,think,suppose,plan,mean,intend等的过去完成时,后接不定式to do时,表示未曾实现的希望或打算,即“本来希望或打算做某事(但却没做) ”.如：
I had hoped to send him a Christmas card,but I forgot to do so.我本来希望寄给他一张圣诞卡的,但我忘了寄了.
I had intended to come over to see you last night,but someone called and I couldn’t get away.昨晚我本想去看你的,但有人来了我走不开.
■用于下列4个特殊句型中：
1.hardly…when…,no sooner…than…
2.It/ That /This was the first time that…
3.It was+时间段+since…
4.…than sb.had thought /expected /hoped /wanted等.
Hardly had I opened the door when he told me.我刚开开门,他就告诉了我.
He had no sooner bought the car than he sold it.他刚买了这辆车,转眼又卖了.
It was the second time he had been out with her.这是他第二次和她一道出去.
It was more than a year now since he had seen her.他上次见她以来已经一年多了.
We arrived earlier than we had expected.我们到得比预料的早.
