By the time he retires, he will have worked for 35 years.

　　到退休时，他将工作满35年。

　　[即时演练1]　

　　(1)选词填空：when, while, as, by the time

　　①When I went into the classroom, he was reading.

　　②When/By_the_time I arrived, the film had already ended.

　　③While I am willing to help, I do not have much time tomorrow.

　　④While/When she was making a call, I entered her room.

　　⑤As you grow older, you'll know better and better about yourself.

　　(2)完成句子

　　①As_time_went_on (随着时间的推移), his sight became worse and worse.

　　②My wife kept silent while/when_I_was_working (当我工作的时候)．

　　③The students took notes as_they_listened (一边听)．

　　④I was_about_to_go_to_bed_last_night (昨晚正要上床睡觉) when I heard a cry for help.

　　⑤By_the_time_you_receive_the_letter (等你收到这封信的时候), I will_have_left (将已经离开) the city for my hometown.

　　二、过去完成时

　　1．基本用法

　　过去完成时的构成为"had＋过去分词"。主要用法如下：

　　(1)表示某一动作或存在的状态发生在过去某一时间或某一动作之前，即"过去的过去"。

　　By the end of last week, theyhad finishedthe work.

　　到上周末为止，他们已经完成了工作。

　　When Jack arrived, he learned Mary had been away for almost an hour.

　　当杰克到时，他得知玛丽已经离开快一个小时了。

　　[名师点津]　过去完成时常常用在宾语从句中，从句谓语动作发生在主句谓语动作(过去时)之前。

　　She saidthat she had finished her homework.

　　她说她已完成家庭作业了。

　　(2)某些动词的过去完成时表示过去未实现的希望、计划或打算。常用的动词有hope, expect, suppose, think, want, wish等。

　　They had wantedto help but couldn't get here in time.

他们本来想要来帮忙的，但未能及时赶到这儿。