实意动词：
即行为动词，表示动作的动词。实义动词与系动词是相对的，能独立用作谓语。
它分为及物动词和不及物动词两种：
及物动词是指后面要求有直接宾语的动词；
不及物动词指后面不需要跟宾语的动词。

实意动词使用方法：
及物动词
后面必须跟宾语意义才完整的实义动词，叫做及物动词(transitive verb)。如：
I believe that the committee will consider our suggestion.我相信委员会将会考虑我们的建议。
“How long can I keep the book ?”Harry asked.哈里问：“这本书我可以借多久?”
Dr. Bethune set us a good example. 白求恩大夫给我们树立了好榜样。
Crude oil contains many useful substances.原油含有许多有用的物质。

不及物动词
本身意义完整后面不须跟宾语的实义动词，叫做不及物动词(intransitive verb)。如：
Birds fly.鸟会飞。
It happened in June 1932.这件事发生于一九三二年六月。
My watch stopped.我的表停了。
She spoke at the meeting yesterday evening. 她在昨天晚上的会上发了言。

兼作及物动词和不及物动词
英语里有不少实义动词可以兼作及物动词和不及物动词。这样的动词又有两种不同的情况
a)兼作及物动词和不及物动词时，意义不变。试比较：
Shall I begin at once?我可以立刻开始吗?(begin作不及物动词)
She began working as a librarian after she left school.她毕业后当图书馆管理员。(began作及物动词)
When did they leave Chicago?他们是什么时候离开芝加哥的？(leave 作及物动词)
They left last week. 他们是上周离开的。(left 作不及物动词)
b)兼作及物动词和不及物动词时，有时意义不尽相同。如：
Wash your hands before meals.饭前要洗手。
Does this cloth wash well? 这布经得起洗吗?

英汉实意动词用法比较：
与汉语的比较，有时英语动词的及物和不及物的用法，与汉语的用法不一样，请注意下列两种情况：
a)有的动词在英语里只能用作不及物动词，而汉语则可用作及物动词，如arrive到达，agree同意，listen听。英语里这些动词后面常接介词。如：
We arrived at the railway station at noon.
我们于中午到达火车站。(at不能省去)
(比较：We reached the railway station at noon.)
Everybody listened to the lecture with great interest.
每个人都很有兴趣地听讲课。(to不可省去)
(比较：We all heard the lecture.)
Do they agree to the plan?他们同意这个计划吗?(to不可省去)

b)有的动词在英语里能用作及物动词，而在汉语里则不能用作及物动词，如serve为…服务。
Our children are taught to serve the people wholeheartedly.
我们的儿童被教以全心全意为人民服务
用于be动词之后，实义动词之前。

 实意动词的用法：
肯定句：
主语+动词过去式+其它
否定句：
主语+助动词didn‘t+动词原型+其他
一般过去式：
Did+主语+动词原型+其他

现在完成时:
过去发生并且已经完成的动作对现在造成影响或后果，过去某一时间开始并一直持续到现在的动作或状态。
基本结构：主语+have/has+动词的过去分词
句式：
1. 否定句式：现在完成时的否定句式是“haven't （hasn't）＋过去分词...”。
如：I have not seen the movie yet. 我还没看这部电影。
2. 一般疑问句：Have（Has）+主语+过去分词...？ 如：
—Have you finished the work？你已经做完这项工作了吗？
—Yes, I have. 是的，我已经做完了。（No, I haven't. 不，我还没有做完。）
3. 特殊疑问句：特殊疑问词+have（has）+主语+过去分词...？如：
How many times have you been to the Great Wall？你去过长城几次？
提示：肯定句中有some, already时，改为否定句或疑问句时通常要分别改为any, yet。如：
I have already finished my homework. 我已经完成了我的作业。
→ I haven't finished my homework yet. （否定句）
→ Have you finished your homework yet? （一般疑问句)
现在完成时常见两种句型：
①for短语
②It is＋一段时间＋ since从句
现在完成时特点：
1. 非持续性动词的完成时的肯定式不能与时间段连用，若要用时间段状语，则应换成相应的持续性动词或状态动词。
例如：
He has left.
He has been away for an hour.
2. have/has been to 表示曾经去过某地，但现在不在那；have/has gone to表示现在已去某地，现在不在这。
例如：
He has been to Canada, but now he is working in our company.
Mr. Li in not at home. He has gone to Shanghai.
3. 完成时的肯定式常用already,而否定式和疑问式常用yet，但若already用于疑问句时，表示一种出乎意外的惊讶。
例如：Have you read it already?
现在完成时和一般过去时区别:
现在完成时和一般过去时都表示在过去完成的动作。
但现在完成时强调的是这一动作与现在的关系。如对现在产生的结果或影响等，
而一般过去时只表示动作在过去某一时刻发生，不表示和现在的关系。
比较:
I have lost my new book.  我把新书丢了。（现在还未找到）
I lost my new book yesterday. 我昨天把新书丢了。（昨天丢的，现在找到与否没说明）

have been(to)与have gone( to)的区别：
have been(to)表示“去过某地（现在已经回来了）”，可用于各人称；
have gone(to)表示“去某地了（说话时某人不在当地）”，常用于第三人称，
前者可与once ,never,several times等连用，后者则不能。
如：
They have been to Beijing twice.他们去过北京两次。
He has gone to Beijing .  他去北京了。

现在完成时注意事项:
1.如单纯表示一段时间，或强调一段时间，虽有since一词，也不必用完成时。如：
It is two years since his father died. =His father has been dead for two years.他父亲去世已有三年了。

2.终止性动词现在完成时的否定式，已变成一种可以延续的状态，因此可以和表示一段时间的状语连用。如：
I haven't left here since 1997.自从1997年以来，我一直没有离开过这儿。

3..现在完成时不能单独与准确时间连用，（如表示过去的时间状语）
如:yesterday(morning、afternoon),last(morning、afternoon）等，除非与for,since连用.

4.不能与when连用.

现在完成时的用法：
1.表示动作发生在过去某个不确定的时间，但对现在留下了某种影响和结果。常被just、already、yet 等副词修饰。如：
-Have you had lunch yet?    
-Yes,I have. I've just had it.
2.表示从过去某一时刻开始一直持续到现在的动作或状态。这个动作可能刚停止，可能仍然在进行。
常带有for和since等表示一段时间的状语。如：
He has taught here since 1981
他自1981年就在这儿教书。（可能还要继续教）
I have't seen her for four years.
我有四年没见到她了。
3.表示说话前发生过一次或多次的动作，现在成为一种经验，一般译为汉语“过”。
常与twice,ever,never,three times等时间状语。 如：
I have been to Beijing twice.我去过北京

4. 现在完成时还往往可以同包括现在时间在内的时间状语连用，如：
now,up to these few days/weeks/months/years,this morning/week/month/year,just,today,up to present,so far等：
Peter has written six papers so far.
Man has now learned to release energy from the nucleus of the atom.
There has been too much rain in San Francisco this year.
The friendly relations and cooperation between our two countries have been enhanced in the past few years.
Up to the present everything has been successful.

5.现在完成时往往同表示不确定的过去时间状语连用，如：
already（肯定），yet（否定，疑问），just,before,recently,still,lately,never等：
He has already obtained a scholarship.
I haven't seen much of him recently (lately).
We have seen that film before.
Have they found the missing child yet?

6.现在完成时的"完成用法"
现在完成时的"完成用法"指的是动作发生在过去某一时刻并已结束，但该动作对现在产生了影响，与现在情况具有因果关系。
例如：
He has turned off the light.他已把灯关了。（动作结束于过去，但说明的是现在的情况--灯现在不亮了。）
现在完成时"完成用法"的特点是动作不延续，因此：
该时态只能与表示不定的过去时间状语（如：already，yet，before，recently等）、频度时间状语（如：never，ever，once等）、包括现在时刻在内的时间状语（如：this morning / month /year...，today等）连用。
例如：Have you found your pen yet？你已找到你的钢笔了吗？
7.现在完成时的"未完成用法"
现在完成时的"未完成用法"指的是动作开始于过去某一时刻，一直延续到现在，或可能还要继续下去。
例如：
He has lived here since 1978.自从1978年以来，他一直住在这儿。
（动作起始于1978年，一直住到现在，可能还要继续住下去。）
I have been in the army for more than 5 years.我在部队已经呆了五年多了。
（动作开始于5年前，一直延续至今，有可能还要继续下去。）
此种用法的句中常需一个表示一段时间的状语（由since或for引导），或表示与现在时刻相连的时间状语（如：up to now，so far）等。
例如：
I have heard nothing from him up to now.到目前为止我没有他的任何消息。
注意：现在完成时的未完成用法只适用于延续性动词，不可用于终止性动词，即瞬间完成或延续时间很短的动词。
如：come，go，arrive，leave，join，become，die等。
8.一段时间+has passed+since从句
主语＋have / has been＋since短语
例如：He has been in the League for three years.
或It is three years since he joined the League. 他入团已三年了　　
9. 现在完成时常和短语 "up to now /till now","so far" （意思是从过去某一确定的时间一直延续到现在)连用。　　
Up to/till now he's read many story books. 至今他已读过好多故事书。
I've been to New York three times so far. 至今我已到纽约去过三次。
has gone (to),has been (to),has been (in) 的区别
has gone to：去了没回
has been to ：去过
has been in：呆了很久

直接引语和间接引语：
引用别人的话有两种方式，一种是讲述别人的原话，并把它放在引号里，这叫直接引语；
另一种是用自己的话来转述别人，并且不能用引号，这就是间接引语。直接引语和间接引语之间可以互相转换。

直接引语和间接引语关系:
直接引语：直接引述别人的话（句子中有“”）。
间接引语：用自己的话转述别人的话，叫“间接引语”（句子中一般无“”） 
间接引语在大多数情况下是一个宾语从语。直接引语变成间接引语时，要注意以下几点：
人称变化、时态变化、宾语从句要用陈述句语序。
1.直接引语是陈述句，变成间接引语时，由连词that 引导。例如：
She said, "I am very happy to help you."→She said that she was very happy to help you.
2. 直接引语是一般(选择/反意)疑问句，变成间接引语时，由连词whether或if 引导。例如：
He asked me, "Do you like playing football?"→He asked me if/whether I liked playing football.
注意：大多数情况下，if和whether 可以互换，但后有or not,或在动词不定式前，或放在介词后作连接词时，一般只用whether。例如：
She asked me whether he could do it or not.
He hesitated about whether to drive or take the train.
3. 直接引语是特殊疑问句，变成间接引语时，由相应的疑问词who, whom, whose, how, when, why, where 等引导。例如：
My sister asked me, "How do you like the film?"→My sister asked me how I liked the film.
4. 直接引语是祈使句，变成间接引语时，把动词原形变成动词不定式，并在动词不定前加tell, ask, order 等的宾语。例如：
The captain ordered, "Be quiet."→The captain ordered us to be quiet.
注意：此种情况的否定句，在动词不定式前加not。
My teacher asked me, "Don't laugh."→My teacher asked me not to laugh.

 一些注意事项:
(1)如果直接引语是表示客观真理时，变为间接引语，一般现在时不改为一般过去时。如：
The teacher said "The earth goes round the sun."
→The teacher said that the earth goes round the sun.
(2)如果直接引语中有明确表示过时间的状语，变为间接引语时，一般过去时不改为过去完成时。如：
He said to me, "I was born in 1973."
→He told me that he was born in 1973.

(3)如果直接引语所述事实在当时和目前同样生效，变为间接宾语时，一般现在时不改为一般过去时。如：
He said, "I'm a boy, not a girl."
→He said that he is a boy ,not a girl.

(4)如果直接引语中的谓语动词表示一种反复出现或习惯动作，
在变为间接引时，一般现在时不改为一般过去时。如：
The girl said, "I get up at six every morning."
→The girl said that she gets up at six every morning.

(5)如果直接引语中含有since, when, while 引导的表示过去时间的状语从句，
在变为间接引语时，只改变主句中的谓语动词，从句的一般过去时则不变。如：
He said to me, "I have taught English since he came here ."
→He told me that he had taught English since he came here.

(6)如果直接引语中含有情态动词 must, need, had better以及情态动词的过去式could, might, should, would,
在变为间接引语时，这些情态动词没有时态的改变。例如：
The teacher said to me . "You must pay more attention to your pronunciation."
→The teacher told me that I must (have to ) pay more attention to my pronunciation.
He said , "I could swim when I was only six ."
→He said that he could swim when he was only six.
 
(7)间接引语一般要用陈述句的语序，即主、谓、宾的顺序。例如：
He asked Lucy, "Where did you go?"→He asked Lucy where she went.
Tom said, "What do you want, Ann?"→Tom asked Ann what she wanted.

直接引语变间接引语:
A.一般不表示请求或祈使的句子改为一个宾语从句
1.连词
若直接引语引号里的内容是陈述句，那么改为间接时，要用连词 that (可以省略)
……………….一般疑问句，…….，要用连词 if/whether (不可以省略)
……………….特殊疑问句，…….，要用连词 wh- 即特殊疑问词本身（不可省）
2.变化
（1）主句动词的变化
一般说来，主句谓语动词常为said或said to，变为间接引语时，当直接引语是陈述句时，said不变。
当直接引语是一般疑问句和特殊疑问句时，则要把said或said to变为asked / asked sb.
（2）从句人称的变化
由直接引语变间接引语时，从句的主语人称要遵循一主、二宾、三不变的原则。
①直接引语的主语是第一人称变为间接引语时要和主句的主语保持一致。
②如果直接引语的主语是第二人称变为间接引语时要与主句的宾语保持一致。
③如果直接引语的主语是第三人称变为间接引语时，人称不变。例如：
①They said, “We will go there by bus.” →They said they would go there by bus.
②She said to me, “Are you interested in science?” →She asked me if I was interested in science.
③His mother said to me, “He can't go to school.” →His mother told me that he couldn't go to school.
（3）、从句动词时态的变化
a. 如果主句的时态是一般过去时，从句的时态则应是与主句时态相应的过去时态。
①一般现在时→一般过去时；
②一般过去时→过去完成时；
③现在进行时→过去进行时；
④现在完成时→过去完成时；
⑤过去完成时→过去完成时（不变）；
⑥一般将来时→过去将来时。例如：
The girl said, “I'm sorry for being late for class.” →The girl said that she was sorry for being late for class.
b. 直接引语变为间接引语时，如果主句中的谓语动词是一般现在时或一般将来时，则间接引语从句的时态保持不变。例如：
He says, “I have finished my homework.” →He says that he has finished his homework.
She will say, “I'll do it tomorrow.” →She will say that she'll do it the next day.
c. 直接引语如果是客观事实或真理，变为间接引语时，从句时态不变。例如：
The teacher said, “The earth moves around the sun.” →The teacher said that the earth moves around the sun.
（4）、指示代词、时间状语、地点状语和动词的变化
直接引语变为间接引语时，指示代词的变化为this→that， these→those等；
时间状语的变化为now→then， today→that day， yesterday→the day before, tomorrow→the next day等；
地点状语的变化为here→there；动词的变化为come→go（go 不要变come）。例如：
1. She said, “I will come this evening.” →She said that she would go that evening.
2. He said, “My sister was here three days ago, but she is not here now.” →He said that his sister had been there three days before, but she was not there then.

B.表示请求或祈使的句子改为句型tell/ask/order sb (not) to do sth
当直接引语引号里的内容表示要求时用tell sb (not) to do sth
当直接引语引号里的内容表示请求时用ask sb (not) to do sth
当直接引语引号里的内容表示强制要求时用order sb (not) to do sth

“It”用法及其句型和固定搭配，是英语语法的重点、难点，又是近几年考试的热点，因此在复习中应给予足够的重视。
It 句型归纳：
1． It is ＋adj．(＋for sb．／sth．) ＋ to do sth．
用于此句型的形容词有：easy， hard， difficult，possible， important， impossible， necessary， good， bad， exciting， interesting， surprising等。如：
 It is necessary to change your job．
 It was very hard for them to walk such a long way in the snow．
2．It is ＋n．(＋for sb．／sth．) ＋ to do sth．
用于此句型的名词有： pity, shame, pleasure, one’s duty, one’s job, fun, joy, good manners, bad manners等。如：
 It is a pity for you to have missed such a wonderful play．
 It is bad manners for the young to take up the seats for the old．
3．It is ＋adj．＋of sb．＋to do sth．
此句型中的形容词主要描述某人的品德、特征。能用于该句型的形容词有： kind, nice, wise,
silly, polite, impolite, friendly, foolish, clever等。如：
 How silly it was of you to give up such a good chance！
 It is friendly of the family to try to make me feel at home in their house．
4．It is ＋adj．（＋n．）＋doing sth．
此句型中的形容词和名词常见的有：no／little use, no／much good, useless等。如：
 It’s no use crying over spilt milk．
5．It takes sb．＋一段时间＋to do sth． 表示“做某事花费某人多长时间”。如：
It took us half an hour to ride to the town by the sea．
6．It is ＋及物动词的过去分词＋that从句
此句型中常见的及物动词的过去分词有：said, told, known, reported, recorded, thought, believed, considered等。如：
It is reported that the Russian President will visit China next week．
7．It ＋不及物动词＋that从句
此句型中不及物动词常见的有：seem， happen， appear， matter等。如：
 It seems that there will be a heavy snow tomorrow．
 It happened that I met my good friends in the museum yesterday．
8．强调句型：It is＋被强调部分＋that／who从句
在使用强调句型时要注意，指人时可以用who或that，其它情况一律用that。如：
 It was under the bed that my brother hid the ball this morning．
 It is Mr Bell who／that often comes and looks after the old man．
9．It is／has been＋一段时间＋since从句。如：
It is ／has been three years since we saw each other last．
10．It is (high) time that sb． did sth．
该句型表示“某人现在该做某事了”，从句常用过去时（虚拟语气）说明现在应该做的事情。如：
 It’s six o’clock．It is high time that we went home now．

It 常用的固定搭配：
1. make it
（1）在口语当中相当于succeed，表示：成功、做到、说定、赶上、及时到达
例  It's hard to make it to the top in show business.
（2）在口语中相当于fix the date for，表示“约定好时间”
例  —Shall we meet next week？
—OK. We just make it next Saturday.
2. as it is
（1）相当于in fact，in reality表示“事实上，实际情况是……”
例  We had planed to finish the task today，but as it is we probably won't finish it until next week.
（2）相当于方式状语从句，表示“照原样”
例  Leave the table as it is.
3. as it were
相当于as one might say，that is to say，表示“也就是说，可以说，换句话说”
例  He is，as it were，a modern Sherlock Holmes.
4. if it weren't for…/if it hadn't been for…
用来引导虚拟语气，相当于without，or but for，表示“如果不是……，要不是……”
例  If it weren't for Tom，I wouldn't be alive today.
5. that's it
（1）相当于That's all. That's so much. 表示“至此为止，没有别的了”
例  You can have one more sweet，and that's it.
（2）相当于 That's right.表示“对啦”
例  — I guess the key to the problem is thechoice “A”
—That's it.
6. catch it
在口语中，相当于be punished/scolded for doing sth. wrong. 表示“因做错事而挨骂，受责备，受批评，受惩罚”
例  We'll really catch it form our teacher if we're late for class again.
7. have it
（1）相当于say，insist表示“说，主张，表明，硬说”
例  Rumour has it that they are getting divorced.
（2）相当于get to know something，表示“了解，知道，获悉”
例  I had it from John that she was going abroad.
8. have what it takes
在口语中，相当于be well qualified for，表示“具有成功的条件”
例  You can take it from me that your daughter has what it takes to be a star.
9. so it seems / appears.
10. Keep at it！（Don't give up！）
相当于go on，表示“继续做，不放弃”
例  My teacher asked me to keep at it.
11. Go it！（Go on！）拼命干，莽撞
12. Now you have done it！（You have done sth. wrong.）
13. Now you'll catch it！（You'll be punished.）
14. As it happened，…
在口语中，相当于it's a pity that…，表示“真不凑巧，真遗憾”
例  As it happened，they were out.
15. As it turned out，…
在口语中，相当于it was found to be in the end，表示“最后被证明是”
例  As it turned out，his statement was false.
16. Such as it is（they are）
在口语中，相当于although it may not be worth much，表示“虽然没有多大价值”
例  You can borrow my exam notebook，such as it is.
17. Take it/things easy.
相当于Don't worry or don't hurry. 用来劝告别人，表示“不要慌，别担心，存住气”
例  Take it easy！ He will do it well.
18. Take it from me.
在口语中，相当于believe me what I say.表示“请相信我的话，我敢担保”
例  You can take it from me that he will make it this time.
19. For what it is worth…
在口语中，相当于although I'm not sure it's of value，表示“不管其价值如何”
例  Here is the article I promise you，for what it's worth.
20. Worth it
在口语中，相当于useful，表示“有好处，值得做”
例  Don't hesitate about it！ It's worth it.
21. Believe it or not.表示“信不信由你”
例  Believe it or not，Tom is getting married to Mary next Sunday.
22. Take it or leave it. v. 要么接受要么放弃
例  That is my last offer. You can take it or leave it.
23. It all depends/that all depends
在口语中，相当于it hasn't been decided yet，表示“那得看情况，还没有定下来”
例  —Are you going to the countryside for holiday？
—It/That all depends.
24. It's up to sb.
在口语中，相当于it's decided by sb. 表示“由……决定，由……负责，取决于……”
例  —Shall we go out for dinner？
—It's up to you.

it用法小结：
It用作实词
表达以下概念:
指代前文提到的事物，前文中的this, that；
替代前文中的内容；
指代一位性别不明的小孩或未知的人；
指代未指明但谈话双方都知道的那件事；
指代时间、天气、气候、距离等自然现象。

一、it 作人称代词的用法
1. 指事物
作为人称代词，it 可以除人以外的一切事物或动物。如：
I dropped my watch and it broke. 我把手表掉在地上摔坏了。
It’s hard work, but I enjoy it. 工作很辛苦，可是我乐意干。
“Where is the dog?” “It’s in the bedroom. ” “狗在哪?”“在卧室里”。
2. 指人
it 指人主要用于指不性别不明的婴儿或用于确认某人的身份。如：
Is it a boy or a girl? 是男孩还是女孩?
There is a knock on the door. It must be the postman. 有人在敲门，一定是邮递员。
【说明】在答语中，常用来指本人，如说 It’s me。
3. 代替某些代词
代词 it 还可用于代替指示代词this, that 以及复合不定代词 something, anything, nothing等。如：
“What’s this?” “It’s a new machine. ” “这是什么?”“是一种新机器”。
Nothing is wrong, is it? 没出什么问题，是吗?

二、it 作非人称代词的用法
1. 基本用法
it 作非人称代词的用法，主要用于指时间、距离、价值、天气、气候及温度等自然现象。如：
It’s too late to go there now. 现在去那儿已经太迟了。
It rained all day yesterday. 昨天下了一天的雨。
It can get very hot here. 这里有时会很热。
2. 用于某些句型
It’s time for sth. 该做某事了。
It’s time to do sth. 该做某事的时候了。
It’s time for sb to do sth. 某人该干某事了。
It’s (about / high) time + that-从句. 某人该做某事了。(从句谓语用过去式，有时也用“should+动词原形”)
It’s first (second) time + that-从句. 某人第几次干某事。(从句谓语用现在完成时)
It’s + 时间段 + since-从句. 自从……有一段时间了。
It’s + 时间段 + before-从句. 过多长的时间才……

三、it用作形式主语
1. 基本用法
当不定式、动名词、从句等复杂成分用作句子主语时，为保持句子平衡，通常把真正的主语放在句末，而在句首使用形式主语it。如：
It’s very important to remember this. 记住这一点很重要。
It’s hard work climbing mountains. 爬山是费劲的事。
It’s unknown when he will come. 他什么时候来还不知道。
2. 用作形式主语的的重要句型
(1) It + be + adj. for (of) sb to do sth 某人做某事……
It is hard for him to make up his mind. 他很难下定决心。
It was foolish of her to say such a thing. 她说那样的话，真是太蠢了。
【说明】介词 of 与 for 的区别是：
of 用于指某人的性格、属性、特征等，介词for表示对象，意为“对……来说” 。
(2) It takes sb + 时间段 + to do sth. 某人做某事花了……时间
It takes years to master a new language. 要花多年的时间才能掌握一门新的语言。
【说明】此句型可以有以下多变种变体：It took me an hour to write the letter.
=The letter took me an hour (to write). =I took an hour to write the letter. 我写这封信花了一个小时
(3) It is up to sb to do sth. 该由某人做某事
It’s up to you to to make the choice. 得由你来作选择。
(4) it look (seem, appear, happen, occur) that [as if]… 似乎……
It seemed as though he didn’t recognize me. 他似乎没认出我来。
It happened that I was out when he called. 他打电话时我碰巧不在家。
(5) If it were not for… / If it hadn’t been for… 若不是因为……
If it were not for their help, we couldn’t have got over the difficulties. 要不是他们帮助，这些困难我们不克服不了的。

四、it用作形式宾语
1. 基本用法
当不定式、动名词、从句等复杂成分用作宾语且其后跟有宾语补足语时，通常会在宾语补足语前使用形式宾语，而将真正的宾语移至句末。
其基本结构为“动词+it+宾语补足语+不定式(动名词或从句)”。如：
I find it difficult to do the job well. 我发现做好这件事不容易。
I think it best that you should stay here. 我认为你最好住这儿。
We think it no use complaining. 我们认为抱怨是没有用的。
2. 用作形式宾语的几个特殊结构
(1) 动词+ it + that-从句。如：
I like it that you came. 你来了，我很高兴。
I take it (that) he will come on time. 我认为他会准时来的。
You can put it that it was arranged before. 你可以说这是以前安排的。
Rumor has it that the defence minister will soon resign. 据传闻，国防部长不久就要辞职。
【说明】能用于此结构的动词不多，常见的有 have, take, put, like 等。
(2) 动词 + it + when (if)-从句。如：
I dislike it when you whistle. 我不爱听你吹口哨。
We really appreciate it when she offered to help. 她来帮忙了，我们十分感激。
I’d prefer it if I didn’t have to do so much work. 要是我不必做那么多工作，好就太好了。
【说明】能用于此结构的动词不多，常见的有 enjoy, hate, love, like, dislike, appreciate, prefer 等。
(3) 动词 + prep + it + that-从句。如：
See to it that you’re not late again. 注意千万不要再迟到。
Look to it that this doesn’t happen again. 注意不要再发生这种事。
You may rely on it that he’ll come to meet you. 你放心，他会来接你的。
I can’t answer for it that he will come. 我不能保证他会来。
【说明】能用于此结构的动词不多，常见的有see to, look to, insist on, stick to, depend on, answer for 等。
(4) 动词 + it + 介词短语+ that-从句。如：
I owe it to you that I am still alive. 多亏有你我才仍然活着。
I took it for granted that he would help us. 我认为他会帮助我们的。
【说明】能用于此结构的动词不多，常见的有take it for granted, bring it to sb’s attention, owe it to sb 等。

it在强调句中的使用
It is＋被强调部分＋that(who)＋其他
在使用强调句型时需注意以下几点：
1. 请注意强调句型的特殊疑问句 
2. 在强调原因状语从句时，只能强调由because所引导的从句。
3. 在强调not … until结构时必须把not与until一起放到被强调的位置上。
4. 注意强调句型与定语从句的区别。
5. 不管被强调部分是单数还是复数，其前一律用It is / It was，而不能用They are / There were之类的。
6. 被强调部分是指人时，被强调部分后可用that / who，被强调部分指物时，被强调部分后只能用that。
7. 被强调部分是指时间或地点时，被强调部分后通常用that，一般不用when，where之类的。例：
It is I who am right. 是我对。
It was you that were wrong. 是你错了。
It was in the Japan that he died. 他是死于日本。
It was yesterday that he got married. 他是昨天结婚的。
It was a computer that he bought last week. 他上个星期买的是一台电脑。
Where was it that she lived? 她是住在什么地方?
When was it that he left for Japan? 他是什么时候离开去日本的?
Who is it that teaches you English? 是谁教你们英语?

定语从句：
担任定语动能的句子称为定语从句。定语从句在句中的作用相当于形容词，故又称为形容词性从句。
定语从句所修饰的词叫先行词；定语从句一般用关系代词或关系副词来引导，关系词放在先行词与定语之间起连接作用，同时又作从句中的一部分。

定语从句的分类：
根据定语从句与先行词的关系，定语从句可分为限制性定语从句及非限制性定语从句。
限制性定语从句紧跟先行词，主句与从句不用逗号分开，从句不可省去;
非限制性定语从句主句与从句之间有逗号分开，起补充说明作用，如省去，意思仍完整。
1．由that引导的定语从句
一般情况下that可指人或物，可以代替who，whom和which，在从句中作主语或谓语动词的宾语，但不能作介词的宾语。如：
The comrade that（who）is speaking at the meeting is an advanced worker．
正在会上讲话的那个同志是个先进工人。
Is this the doctor that（whom）you talked about yesterday？
这就是你们昨天谈论的那位医生吗？
The letter that（which）I received yesterday was from my father．
昨天我收到的信是我父亲寄来的。
2．由who，whom和whose引导的定语从句
who在从句中作主语，whom在从句中作宾语，whose在从句中作定语。如：
This is the thief who stole my bike．这就是偷我自行车的那个贼。
He is the boy whom you wanted to find．他就是你想要找的那个男孩。
The girl whose mother is a doctor is waiting for you outside．妈妈是个医生的那个女孩在外面等你。
3．由which引导的定语从句
which指物，在从句中作主语或谓语动词的宾语。如：
The book which Mum bought me last week is called“Red Star Over China”．
妈妈上周买给我的那本书名叫《西行漫记》。
The house which Lu Xun once lived in is now the Lu Xun Museum．
鲁迅曾经住过的那所房子现在是鲁迅博物馆。
4．由where，when和why引导的定语从句
where在从句中作地点状语，when在从句中作时间状语，why在从句中作原因状语。如：
I will never forget the day when I joined the League．我永远忘不了我入团的那一天。
He will go back to the school where he studied next week．下周他要回到他曾经学习过的学校。
I don't know the reason why he quarreled with Zhang Lin．我不知道他同张琳吵架的原因。
［注意点］
关系代词在定语从句中作宾语时，关系代词常省去。如：
The play（which）I watched just now had been on twice on Channel
我刚才看的那个戏剧在3频道上已上演了两次。

限定性定语从句：
1. that即可代表事物也可代表人，which代表事物；
它们在从句中作主语或宾语，that在从句中作宾语时常可省略关系词，which在从句中作宾语则不能省略。
而且，如果which在从句中作“不及物动词＋介词”的介词的宾语，注意介词不要丢掉，而且介词总是放在关系代词which的前边，但有的则放在它原来的位置
2. which作宾语时，根据先行词与定语从句之间的语义关系，先行词与which之间的介词不能丢
3. 代表物时多用which，但在带有下列词的句子中用that而不用which，这些词包括all, anything, much等，这时的that常被省略
4. who和whom引导的从句用来修饰人，分别作从句中的主语和宾语，whom作宾语时，要注意它可以作动词的宾语也可以作介词的宾语
5. where是关系副词，用来表示地点的定语从句
6. when引导定语从句表示时间
〔注〕值得一提的是，表示时间“time"一词的定语从句只用when引导，有时不用任何关系代词，当然也不用that引导
By the time you arrive in London, we will have stayed there for two weeks.
I still remember the first time I met her.
Each time he goes to besiness trip, he brings a lot of living necessities, such as towers, soap, toothbrush etc.
7. whose是关系代词，修饰名词作定语，相当于所修饰成分的前置所有格
8. 当从句的逻辑主语是some, any, no, somebody, anybody, nobody, something, anything, everything或nothing时，常用there is来引导

非限定性定语从句
非限定性定语从句的作用是对所修饰的成分作进一步说明，通常和主句间用逗号隔开，将从句拿掉后其他部分仍可成立
1. which引导的非限定性定语从句来说明前面整个句子的情况或主句的某一部分
2. 在引导限定性定语从句时，that有时相当于in which, at which, for which或at which
Attitudes towards daydreaming are changing in much the same way that(in which) attitudes towards night dreaming have changed.
人们对白日做梦的态度正在改变，这与人们对夜间做梦的看法的变化有非常相似之处。
I like the music for the very reason that(for which) he dislike it.
我出于某种原因喜欢这种音乐，而他恰恰与我相反。
We arrived the day that(on which) they left.
刚好我们到的那天他们走了。
3. 有时as也可用作关系代词
4. 在非限定性定语从句中，不能用that，而用who, whom代表人，用which代表事物
限定性定语从句口诀:
（口诀一）　　
定语从句真奇妙，　　
关系代(副)词来引导，　　
定语从句分两种，　　
是否限定看逗号。　　
（口诀二）　　
which指物who指人，　　
地点where时间when,　　
that人或物均可，　　
why之前是reason。　　
（口诀三）　　
从句当中作宾语，　　
whom可以代替who,　　
为了句子更简练，　　
关系代词可省去。　　
（口诀四）　　
关系若是表所属，　　
whose用法不可无。　　
除此之外还有啥，　　
whom, which加of。　　
（口诀五）　　
关系代词不一般，　　
介词经常用在前，　　
此时不用that, who，　　
which, whom才安全。　
引导定语从句的关系词：

关系词	词形	所修饰的先行词	在从句中所作的成分
关系代词	who	人	主语、宾语、表语
	whom	人	宾语
	which	物	主语、宾语、表语
	that	人或物	主语、宾语、表语
	as	人或物	主语、宾语、表语
	whose=of whom/of=which	人或物	定语
关系副词	when	时间词	时间状语
	where	地点词	地点状语
	why	原因词	原因状语

关系代词的用法 ：
1. 关系代词的句法功能 
(1)关系代词在句中作主语
例如：I prefer music that/which has great lyrics 
(2) 关系代词在句中作宾语 
例如：I like music that I can sing along with. 
(3)关系代词在句中作表语
例如：The house is not the one (that) it used to be.
2. 关系代词在从句中作名词的定语
例如：Is she the teacher whose hair is very short? 
3. 关系代词的用法 
(1)who和whom的用法：二者都用于指人。Who在定语从句中作主语、宾语，
whom 在定语从句中作宾语。Whom在从句中能坐介词的宾语，而who则不能。
例如：
I happened to meet the professor (who/whom) I got to know at a party 
in the shopping center yesterday.
(2)whose的用法：一般指人，有时也指物。在定语从句中作定语。 
例如：I have got a friend whose brother is training for the Olymoics.
(3)which的用法：一般指物，在定语从句中作主语、宾语、偶尔作定语。 
例如：The photo which we liked best was taken by Zhao Min. 
(4)that的用法：指人或物，指人时可与who、whom互换，指物时可与that互换。
在从句中可作主语、宾语，还可作表语。 
例如：It is a book (that/which) no one really likes. 
4. 宜用who不宜用that的情况 
(1)先行词是指人的不定代词时 
例如：Congratulations to our winners and thanks to everyone who entered the competitions.  
(2) 先行词指人时且含有较长的后置定语     
例如：The boy was crying hard who lost his way while looking for his mother.
5. 在以下情况中，关系代词常用that
(1)先行词为all, little, few, none 及some-, any-, no-与thing所组成的复合单词时，只能用that。
例如：There is nothing that will stop us making progress. 
(2)先行词前有only, some, any等形容词修饰时，只能用that。
例如：This is the only problem that we can’t work out.
(3)先行词前由形容词的最高级或序数词修饰时，只能用that。
例如：This is the most interesting book that I have ever read.
(4)先行词同时包括人和物时，只能用他和她，
例如：Lu Xun and his works that we are familiar with are considered great.
6. 只能用which不能用that的情形
(1)当非限制性定语从句中的先行词指物时，只能用which
例如：The pencil-case, which I bought last week, is missing.
(2)关系代词前面有介词时，只能用which
例如：The tree under which we used to take a rest has been cut down.
(3)先行词本身就是that时
例如：I don’t like that which he did.

关系副词的用法 
1. when的用法：它的先行词通常是time, day, morning等。有时也可和一些介词一起引导定语从句。
例如：Do you remember the time when she went abroad?
2. where的用法：它的先行词通常有place, spot, room等。
例如：I like places where the weather is always warm.
3. why的用法：它的先行词只有reason。Why时常也可以省略。
例如：Tell me the reason why she was late.