高考英语语法精要讲解二十四：过去完成时
1、过去发生的两个动作，先发生的`用过去完成时
With their help I realized that I had been wrong.
2、过去某时以前发生的动作或情况
He hasn’t finished yet.
He didn’t finish yesterday evening.
He hadn’t finished by yesterday evening.
3、常用过去完成时的情况
①No sooner…than…. Hardly…when…
No sooner had he begun his speech than he was interrupted
②expect, hope, think, want, suppose等动词的过去完成时（或一般时）表示想做而未做的事
I had planned to send him a telegram, but I didn’t manage it.
4、使用过去完成时的必要性和非必要性
①句意十分清楚时，可用一般时
After I finished, I went home.
②常用一般过去时表示依次发生的动作
I got out of the taxi, paid the fare（车费) and managed it.
③有时必须明确，特别是含when时
When I arrived, Ann left.
(同时见到）（见到Ann)
When I arrived, Ann had left.
（先后发生）（没见到）
5、常用过去完成时的时间主状语
by the end of +过去时间 ； by + 过去时间
by the time + 过去时间；过去时间 + before
比较：
By the time he was 11, he had learned 3000 words .
By the time he is 11, he will have learned 3000 words.
By the time last week, I had learned 3000 words.
By the time next week, I will have learned 3000 words
That which代表物，区别听我来叙述；
先行若是不定代，that就把which 踹；
当先行词为anything，everything，nothing，all，any，much，many，one等不定代词时，只能使用“that”, 不用 “which”。
例：Is there anything that I can do for you? 我能给你做点什么吗？
先行词前有两数， 就用that定无误；
当先行词是基数词或序数词修饰时，只能使用“that”，不用 “which”。
例句： That is the second time that I have been to Japan. 那是我去日本的第二次。
The two buildings that lay on the River Thames fell down last week.
坐落在泰晤士河岸边的那两座大楼上星期倒塌了。
先行词前最高级， 还用that必无疑；
当先行词是形容词最高级或被形容词最高级修饰时，只能使用“that”, 不用 “which”。
例句：This is the most wonderful time that I have ever had.
这是我度过的最美好的时光。
句中若有there be, that应把which替；
例：There is no evidence that animals possess a mysterious sixth-sense allowing them to predict natural disasters. 说动物拥有神秘的'第六感，可以预知自然灾害，这是没有根据的。
先行主中做表语， 避免重复从句里；
例句：1）This is not the hospital that it used to be.
这已经不再是以前那座医院了。
2）Mr Thomson is not the man that he was.
汤姆森先生已经不再是以前的他了。
解析：定语从句的先行词均在主句中做表语。
例句：Which is the course that we are to take ?
我们要学哪门课？
解析：句中已有which,后面不再用which,避免重复用that。
（Just the only very same last, 其后也要用that;）
先行词前有Just 、the only、 very 、same 、last等词，关系代词用that，不用which。
例句：1) The North Pole is the only place that you can see polar bears.
北极是唯一能见到北极熊的地方。
2）This is the same bike that he lost.
这就是他丢了的那辆自行车。
注意区分：
3) This is the same bike as he lost.
这辆自行车和他丢的那辆一样。（但不是）
从属连词从属连词是用来引导从句的。
1.连词that, if, whether，连接代词what, which, who, whom, whose以及连接副词how, when, why, where可用来引导名词从句，充当主语、表语、宾语等。非正式文体中的宾语从句常省略that：
I think (that) he’ll be back in an hour. 我认为他一小时后就会回来。
Who they are doesn’t matter much. 他们是谁没什么大关系。
Can you tell me where he is? 你能告诉我他在哪儿吗?
He asked me if/whether I knew John. 他问我是否认识约翰。
此外，that, which, who, whom, whose, when, why, where等还可以引导定语从句。
2.连词when, while, before, after, till/until, since, as soon as等引导时间状语从句：
She said hello to me when she saw me. 她看到我的时候，和我打了招呼。
I’ll wait here until you come back. 我将在这里等你回来。
3.连词if, unless引导条件状语从句;because, as, since引导原因状语从句：
I’ll help her if she asks me to. 如果她要求我，我就帮助她。
I won’t help her unless she asks me to. 除非她要求我，否则我不会帮她。
He didn’t come because he was ill. 因为他病了，所以没来。
As he hasn’t appeared yet, we shall start without him. 既然他还没有出现，我们就先开始吧。
Since everybody is here, let’s begin. 既然大家都到了，咱们就开始吧。
4.连词in order than, so that引导目的状语从句;so…that…引导结果状语从句：
I locked the door in order that we might continue our discussions undisturbed. (=I locked the door in order to continue our discussions undisturbed.) 我把门锁上了，以便我们可以继续讨论而不受打扰。
The car ran so fast that I couldn’t see who was in it. 汽车跑得那么快，我没看清谁坐在里面。
5.连词than, as…as…, not as/so…as…用来引导比较状语从句：
He is better educated than his brother. 他比他兄弟受的教育好。
He is as well educated as his brother. 他和他兄弟受的`教育一样好。
He is not as/so well educated as his brother. 他没有他兄弟受的教育好。
6.连词although, though 引导让步状语从句;where, wherever 引导地点状语从句：
I’ll go wherever you go. 不管你去哪儿，我就去那儿。
Stay where you are! 原地别动!
Though/Although she is rich, she’s not happy. 尽管她富有，但她并不幸福。
一般来说，连词性质的连接词连接两个分句或引导一个从句，两个分句或主从复合句之间用逗号连接。
