大学英语精读答案

大学英语精读答案
大学英语精读答案

2) decade

3) content

4) arrange

5) minor

6) efficient

7) endure

8) extra

9) reluctantly

10) tremble

1) bunch

2) packet/pack

3) piece

4) pair

5) piece

6) bunch

7) pair

8) piece

9) bunch

10) packet

11) pair

1) at other times

2) After all

3) efficient

4) endure

5) extraextra

6) round the corner

7) occasions

8) minor

9) arranged

10) primary

11) rare

12) trembling

13) reluctantly

14) disappointment

1) can endure

2) on the occasion of

3) to pick it up

4) are not sure of

5) felt a pang of disappointment

6) Not being content

1) milkman

2) fireman

3) fisherman

4) businessman

5) policeman

6) spaceman

7) weatherman

8) sportsman

1) broadens

2) widened

3) quicken

4) darkened

5) sharpening

6) shortens

1) excitement

2) excited

3) exciting

4) excitedly

6) excited

1) disappointed

2) disappointing

3) disappointed

4) disappointment

5) disappointed

1) patience

2) patient

3) patiently

4) patience

1) reluctant

2) reluctance

3) reluctantly

4) reluctant

1) efficiency

2) efficient

3) efficiently

1) contents

2) content

3) content/contented

4) content

5) contented

6) content

7) contents

8) content

1) The bottle is too small to hold so much water.

2) He was too tired to go any further.

3) He is too proud to see his own shortcomings.

4) It is too late for the bookstore to be open.

5) They did not stop working until it became completely dark.

6) He did not come until the meeting was over.

7) He said he would not get married until he

had found a satisfactory job.

8) He did not go to bed until he had finished his reading assignment.

1) occasion

2) endured

3) rare

4) postman

5) trembled

6) After all

7) at other times

8) disappointment

A

1) necessary

2) and

3) with

4) The

5) of

6) in

7) growing

8) if

9) one

10) through

11) when

12) continue

B

1) present

2) any/those

3) could

4) sing

5) sent

6) cost

7) birthday

8) bird

9) replied

1) journey

2) shocked

3) funeral

4) While there

5) conversations

6) thoughts

7) provide

8) dozens

9) over and over

10) meant

翻译

1) 那位名演员似乎很乐意在剧中扮演一个次要角色。

That famous actor seemed content to play a minor part in the play.

2) 国庆节要到了,咱们把寝室彻底(thorough)打扫一下吧。

National Day is round the corner. Let's give our bedroom a thorough clean.

3) 她非常勉强地同意让一位年轻医生为她做手术。

She agreed, very reluctantly, to be operated on by a young doctor.

4) 他们已安排好让我们明天去游览长城,我相信我们在那儿一定会玩得很开心。

They've arranged for us to visit the Great Wall tomorrow. I'm sure we'll have a good time there (we'll enjoy ourselves there).

5) 老人读完信后失望之极,竟用颤抖的手指把它撕得粉碎。

After reading the letter the old man was so disappointed that he tore it into little bits with trembling fingers.

6) 老两口为他们的孙子感到骄傲,因为他在第28届奥运会上获得了两枚金牌和一枚铜(bronze) 牌。

The old couple were proud of their grandson, who won two gold medals and a bronze at the 28th Olympic Games.

7) 即使他的祖母不能来参加他的生日宴会,她也会寄给他一件可爱的礼物。对这一点汤姆深信不疑。

Even if his grandmother could not come to his birthday party, she would send him a lovely present. Tom was sure of that.

8) 昨天是玛丽的二十岁生日。她父亲寄给她一双靴子,她母亲为她买了一盒巧克力(chocolates),而她的男朋友则带给她一束红玫瑰。

It was Mary's twentieth birthday yesterday.

Her father sent her a pair of boots. Her mother bought her a box of chocolates. And her boyfriend brought her a bunch of roses.

附: Reading Activity及Guided Writing

1) At first the man doesn't want to travel, because he thinks people are the same everywhere.

2) No, the author dosen'tagree with the man.

3) In the author's opinion, people are different.

4) In Korea, old age is a happy time.

5) In Korea the sixty-first birthday is considered a very important event.

6) No. For many North Americans, old age is not a happy time.

7) No, they don't live with their children or relatives.

8) At last, the author concluded that people are different in their customs and cultures.

1)c

2)a

3)d

4)d

5)c

6)b

7)a

8)c

9)c

10)b

1) 再者,虽然所有的人都有着相同的情感,但这些情感的起因却不尽相同。

2) 六十一岁生日之所以有个特别的名称,是因为当人们进入人生的这一阶段时,家庭和社会对他们的态度便有所变化。

3) 如果他们的身体不够健壮,不能单独生活,那他们便住进特设的养老院。

4) 朝鲜和北美都有年轻人和老年人,但年轻时也许待在北美为好,老年时则待在朝鲜为好。

1) I went to visit the American author who

had written a number of books about China.

2) I ate the soup my aunt prepared.

3) It is quite obvious that they need more help in English.

4) It is good news that she is still alive.

5) It doesn't seem likely that she will come here.

6) He suddenly remembered that he had forgotten to take his notebook with him.

7) Can you tell me what kind of show they are putting on?

8) I'm wondering if the letter is overweight.

9) The children who came to the zoo liked the pandas best.

10) Raw material is what we are badly in need of.

大学英语精读3课后答案.doc

大学英语精读 3 课后答案【篇一:大学英语精读第三版第三册课后答案(含 close 原文)】 >1) accent 2) turn against 3) a couple of 4) takes his time 5) fate 6) confirmed 7) witness 8) subsequent 9) stands a chance 10) trial 1) belief 2) brilliant 3) employment 4) has saved up 5) stood a chance 6) were awarded 7) presumably 8) conducted 9) casual 10) around (which student life) revolves 1) joe wrote to say that he had to put off his visit because of his illness. 2) despite the noise, they went on working as if nothing were happening. 3) traffic was held up for several hours by the accident. 4) called (up) on to speak at the meeting, i couldnt very well refuse. 5) mrs. stevenson looked in the cupboard and found there was not a single lump of sugar left. 6) it was the rumor that turned joe against his twin brother. 7) we wondered how sara was getting on in her new job. 8) although anne agreed with me on most points, there was one on which she was unwilling to give in. 9) visitors could photograph almost anything here without having to ask for permission.

大学英语精读第一册答案

大学英语精读第一册答案 大学英语精读第三版第一册答案 Unit1 1) e 2) g 3) j 4) a 5) b 6) i 7) c 8) d 9) h 10) f 1) handling 2) summarized 3) process 4) absorb 5) are bound to 6) feel free 7) for instance 8) strategies 9) complained 10) has committed to memory

11) Nevertheless 12) rely on 13) Apart from 14) command 1) over and over again 2) ata time 3) put it into practice 4) watching out for

5) by no means 6) concentrate on 7) In addition t 8) in detail 1) action 2) employ 3) announce 4) examination 5) communication 6) express 7) compose 8) improvement 9) concentration 10) management 11) consider 12) motivate 13) development 14) movement 15) discuss 16) operate 17) division 18) production 19) educate 20) repeat 1) additional 2) add

大学英语精读第一册(第三版)答案

大学英语精读第三版(上海外语教育出版社董亚芬主编)第一册答案Book 1 Unit 1 Study&Practice Vocabulary Activities 1. 1)e 2)g 3)j 4)a 5)b 6)i 7)c 8)d 9)h 10)f 2. 1) handling 2) summarized 3) process 4) absorb 5) are bound to 6) feel free 7) for instance 8) strategies 9) complained 10) has committed... to memory 11) Nevertheless 12) rely... on 13) Apart from 14) command 3. 1) over and over again 2) at a time 3) put it into practice 4) watching out for 5) by no means 6) concentrate on 7) In addition to 8) in detail Enriching Your Word Power 1. 1)action 2)employ 3)announce 4)examination 5)communication 6)express 7)compose 8)improvement 9)concentration 10)management 11)consider 12)motivate 13)development

15)discuss 16)operate 17)division 18)production 19)educate 20)repeat 2. 1) a) additional b) add c) addition d) addition 2) a) effectively b) effect c) effective d) effect 3) a)helpful b) help c) helpless d) help e) helplessly f) helpfully g) helpful 4) a) reliant b) reliable c) reliance, reliable d) relies e) reliably 5) a) repetition b) repeating c) repeatedly d) repeated e) repetition Usage 1) In my opinion 2) According to Mary 3) In our opinion 4) According to today’s papers 5) In most doctors’ opinion ( According to most doctors) Structure 1. 1) Shakespeare was not only a dramatist but also an actor. 2) Miss Crain not only took me home in her car, but also came the next day to see if I had recovered. 3) Hainan Island attracts tourists not only in winter but also in summer. 4) There is always a black market not only in Britain, but also in other European countries. 5) At the Athens Olympics in 2004, Liu Xiang not only won a gold medal in the 110-meter hurdles, but also broke the Olympic record. 2. 1) It is true that your sentences are all gramma tically correct, but they don’t make any sense. 2) It is true that they lost that battle, but they still went on fighting. 3) It is true that Tom’s very clever and hardworking, but I still don’t think he is the right person for the job. 4) It is true that learning English is by no means easy, but we can make the task easier by using some learning strategies. Cloze 1. 1) strategies 2) frequently 3) over and over again 4) commit to memory 5) acquaintance 6) watch out for 7) communicate 8) process

大学英语精读答案

大学英语精读第二册(第三版)b o o k2U n i t1答案1. bare 2. Empty 3. Empty 4. Bare 5. Empty 6.empty 二) 1. shortly 2.track down 3.faint 4.motioned 5.at the sight of 6.feel like 7.slamming 8.rang out 9.contract 10.made for 11.heated 12.emerged 三) 1. host 2. sprang up/rang out 3. Impulse 4. came to 5. track down 6. Unexpected 7. Outgrow 8. Widened 9. Shortly 10. emerge / spring up 11. at the sight of 12. made for 13. Crisis 14. colonial 四) 1. Jimmy has outgrown the shirts his aunt made for him a few years ago. 2. Does the doctor think the elderly lady is likely to survive the operation / it is likely that the elderly lady will survive the operation? 3. The other day your cousin paid us an unexpected visit. 4. Don't you see the nurse motioning us to be silent? 5. Her face lit up with joy at his return. 6. The sound of her footsteps grew fainter as she walked farther away. 五) 1. Additional advantageous Anxious conditional

大学英语精读第三册 翻译答案

大学英语精读第三版(上海外语教育出版社董亚芬主编) 第三册Book3 Unit1~Unit10 翻译答案 Unit1 翻译 1) 发言人(spokesman)明确表示总统在任何情况下都不会取消(cancel)这次旅行。 The spokesman made it clear that the President would not cancel the trip under any circumstances. 2) 杰克对书架上那些书一本也不了解,所以他的选择是很随意的。 Jack didn't know anything about any of the books on the bookshelf, so his choice was quite arbitrary. 3) 随后发生的那些事件再次证明了我的猜疑(suspicions)是对的。(confirm) The subsequent events confirmed my suspicions once again. 4) 我认为我们应该鼓励中学生在暑假找临时工作。 I think we should encourage high school students to find temporary jobs / employment during their summer holidays. 5) 令我们吃惊的是,这位常被赞为十分正直的州长(governor)竟然是个贪官(corrupt official)。 To our surprise, the governor who had often been praised for his honesty turned out to be a corrupt official. 6) 少数工人得到提升(be promoted),与此同时却有数百名工人被解雇。 A few workers were promoted, but meanwhile hundreds of workers were dismissed.

大学英语精读三答案

北京师范大学网络教育 《大学英语精读三》作业答案 客观题部分: 选择题(每题1分,共20题) 参考答案: 1. B 2. C 3. C 4. D 5. A 6. A 7. A 8. A 9. C 10. D 11. A 12. B 13. B 14. D 15. B 16. A 17. B 18. D 19. A 20. A 主观题部分: 翻译题(每题1分,共10题) 1. The park is located right in the center of town. 2. If you want to make a complaint, you’d better follow the correct procedure. 3. That hairstyle is in fashion this year, but I am afraid it will be out of fashion next year. 4. She waited at the bus stop until the last bus came in. 5. Never before have I met such a kind person. 6. The play was so wonderful that I soon lost myself in the excitement of it. 7. Social activities never get in the way of her studies. 8. He’s working on a new project which has to be finished by the end of the year. 9. In pursuit of a healthier diet, people are eating more fish than they used to. 10.The disease is spreading, and all young children are at risk. 1

大学英语精读第一册课后练习部分答案

大学英语精读第一册课后练习部分答案 Unit 1 Cloze (A) 1. aware 2. performance 3. average 4. adequate 5. set aside 6. mentions 7. look over 8. commit (B) 1. if/once 2. about 3. it 4. know 5. up 6. as 7. from 8. words 9. into 10. other 11. for 12. when Translation 1、他这次考试的失败使他意识到定期复习功课的重要。 His failure in the exam has made him aware of the importance of reviewing his lessons regularly. 2、请一定不要忘记离家前你父母对你说过的话。 Be sure not to forget what your parents said to you before you left home. 3、我确信她的英语知识对这项工作来说是足够的了。 I'm sure her knowledge of English is adequate for the job. 4、这篇文章的目的是告诉学生怎样培养良好的学习习惯。 The purpose of this article is to tell the students how to develop good study habits. 5、在当今时代,人们越来越多地依靠计算机(computers)来解决各种各样的问题。In our age, people depend more and more on computers to solve various kinds of difficult problems. 6、略读不仅可以帮助你对将要阅读的东西有所了解,还可以帮助你读得快些,提高你的阅读理解力。 Skimming not only helps you get some idea of what you are going to read but also helps you read faster and improve your comprehension. 7、有些人以为男孩子比女孩子聪明。然而,事实未必如此。 Some people believe that boys are cleverer than girls. This is not necessarily the case, however. 8、即使智力一般的学生也可以通过改进学习习惯习惯而成为优等生。 Even students of average intelligence can become top students by improving their study habits.

大学英语精读第三版第一册Book1 Unit1-3答案

大学英语精读第三版第一册Book1 Unit1答案 1)e 2)g 3)j 4)a 5)b 6)i 7)c 8)d 9)h 10)f 1) handling 2) summarized 3) process 4) absorb 5) are bound to 6) feel free 7) for instance 8) strategies 9) complained 10) has committed to memory

11) Nevertheless 12) rely on 13) Apart from 14) command 1) over and over again 2) at a time 3) put it into practice 4) watching out for 5) by no means 6) concentrate on 7) In addition t 8) in detail 1)action 2)employ 3)announce 4)examination 5)communication 6)express 7)compose 8)improvement

9)concentration 10)management 11)consider 12)motivate 13)development 14)movement 15)discuss 16)operate 17)division 18)production 19)educate 20)repeat 1) additional 2) add 3) addition 4) addition 1) effectively 2) effect 3) effective 4) effect

大学英语精读三课后翻译题及答案

大学英语精读三课后翻译题及答案 UNIT1-P16 1.发言人明确表示总统在任何情况下都不会取消这次旅行。 The spokesman made it clear that the President would not cancel the trip under any circumstances. 2. 杰克对书架上那些书一本也不了解,所以他的选择是很随意的。 Jack didn’t know anything about any of the books on the bookshelf, so his choice was quite arbitrary. 3.随后发生的那些事件再次证明了我的猜疑是对的。 The subsequent events confirmed my suspicions/ confirmed me in my suspicions once again. 4.我认为我们应该鼓励中学生在暑假找临时工作。 I think we should encourage high school students to find temporary jobs during their summer holidays. 5.令我们吃惊的是,这位常被赞为十分政治的州长竟然是个贪官。 To our surprise, the governor who had often been praised for his honesty turned out to be a corrupt official. 6.只有少数工人得到提升,与此同时却又数百名工人被解雇。 A few workers were promoted, but meanwhile hundreds of workers were dismissed. 7.如果有机会,约翰也许已成为一位杰出的画家了。 Given the chance, John might have become an outstanding painter. 8.数小时后,有人看见那个男孩在林子里瞎转。 Several hours later, the boy was found wandering around in the woods. UNIT3-P59 1.许多美国大学生申请政府贷款交付学费。 Many American students apply for government loans to pay for their education/tuition. 2. 除阅读材料外,使用电影和录像会激发学生学习的兴趣。 Besides reading materials, the use of films and videotapes can stimulate students' interest in a subject. 3.这位律师试图说服陪审团他的当事人是无辜的。 The attorney/lawyer tried to convince the jury of his client's innocence. 4. 提问常常会引起创造的火花。 Asking questions often generates the spark of creativity. 5.我已经把我的简历寄往几家公司,但尚未收到回复。 I have sent off my resume to several corporations, but haven't yet received a reply. 6. 她的结论是建立在对当前国际情况进行了认真的分析的基础上的。 Her conclusion is built on a careful analysis of current international affairs. 7.我们满怀期望地来参加会议,离开时却大失所望。 We came to the meeting full of expectations, yet we left very disappointed. 8.暂时他只得接受了一份给一家化妆品公司发促销传单的活儿。

二十一世纪大学英语精读第三册课后答案

1.Do you think that making music and art compulsory subjects in schools would reduce some children’s enjoyment of them? 2.Bob’s one of those people who relish risk and danger-he’d be bored in a safe ,steady job. 3.Elizabeth is certainly talented enough to succeed in her career; she just doesn’t have enough confidence in her own abilities. 4.I’m sorry you’re in trouble, but as you made your decision on your own you’ll just have to face the consequence. 5.Many educators would be delighted to abolish exams, but they also worry that without them there would be too little incentive for students to work hard. 6.The teacher accidentally hit the boy’s hand with an eraser and was hence force known as “Dead-Eye Bean.” 7.If I had money ,I’d invest it all in internet companies. 8.Psychologist say that our behavior is influenced by many factors too subtle for us to consciously perceive. 9.He’s always had a passion for books. If he could work in a library, it would be a dream comes true. 10.Look at those three whispering in the corner again-they’re scheming something, I just don’t know what! 11.In a healthy relationship,the partners’strengths and abilities complement each other,rather than being identical. https://www.360docs.net/doc/0f8529971.html,lions of dollars and lots of famous actors are not indispensable to the production of a successful film,but they help! 13.I never felt i had a right to expect any special privileges because of my university education. 14.The markeing strategy that Edward proposed would be brilliant if only he hadn’t forgotten about good business ethics. 15.It’s true that not having a car imposes some constraints,but owning one also complicates life in many ways. 16.According to Chinese law,every child is entitled to nine years of free edu. 17.Life should consist of more than juse a stuggle for surrival. 18.The sight of the helpless child aroused her maternal instinct . 19.T he winners of the contest were chosen randomly ,no consideration was given to age,gender or income. 20.He has lost the use of his limbs but he is still in possession of all his faculties. 21.Please give the highest priority to this very urgent. 22.She enjoy parts of her trip to India,but said she she found the poverty she saw there rather depressing . 23.When every student imagines that every other student is working harder and doing better, stress is the inevitable result. 24.It is my firm conviction that violence is never a reasonable solution to conflict. 25.Everyone jumped up when a piercing scream suddenly broke the silence, 26.In many cultures a memorial service is a joyful celebration, not a solemn event. 27.The recession has put increasing pressure on the job market, so employment prospects for this year’s graduates are unfortunately rather grim.

大学英语精读第一册全部答案

Unit 1 Cloze (A) 1. aware 2. performance 3. average 4. adequate 5. set aside 6. mentions 7. look over 8. commit (B) 1. if/once 2. about 3. it 4. know 5. up 6. as 7. from 8. words 9. into 10. other 11. for 12. when Translation 1、他这次考试的失败使他意识到定期复习功课的重要。 His failure in the exam has made him aware of the importance of reviewing his lessons regularly. 2、请一定不要忘记离家前你父母对你说过的话。 Be sure not to forget what your parents said to you before you left home. 3、我确信她的英语知识对这项工作来说是足够的了。 I'm sure her knowledge of English is adequate for the job. 4、这篇文章的目的是告诉学生怎样培养良好的学习习惯。 The purpose of this article is to tell the students how to develop good study habits. 5、在当今时代,人们越来越多地依靠计算机(computers)来解决各种各样的问题。In our age, people depend more and more on computers to solve various kinds of difficult problems. 6、略读不仅可以帮助你对将要阅读的东西有所了解,还可以帮助你读得快些,提高你的阅读理解力。 Skimming not only helps you get some idea of what you are going to read but also helps you read faster and improve your comprehension. 7、有些人以为男孩子比女孩子聪明。然而,事实未必如此。 Some people believe that boys are cleverer than girls. This is not necessarily the case, however. 8、即使智力一般的学生也可以通过改进学习习惯习惯而成为优等生。 Even students of average intelligence can become top students by improving their study habits. Unit 2 Cloze (A) 1. adventure 2. in spite of 3. determined 4.accomplish 5. voyage 6. attempts 7. dissuade 8. give up 9. covered (B) 1. conquer 2. about 3. succeeded 4. between 5. through 6. high 7. sail 8. follow/take 9. round 10. then 11. but 12. As 13. made 14. fast 15. did 16. ever 17. that 18. did Translation

大学英语精读第三版第一册课后习题答案

大学英语精读第三版第一册答案Unit1 1)e 2)g 3)j 4)a 5)b 6)i 7)c 8)d 9)h 10)f 1) handling 2) summarized 3) process 4) absorb 5) are bound to 6) feel free 7) for instance 8) strategies 9) complained 10) has committed to memory 11) Nevertheless 12) rely on 13) Apart from 14) command 1) over and over again 2) at a time 3) put it into practice 4) watching out for 5) by no means 6) concentrate on 7) In addition t 8) in detail 1)action 2)employ 3)announce 4)examination 5)communication 6)express 7)compose 8)improvement 9)concentration 10)management 11)consider 12)motivate 13)development

14)movement 15)discuss 16)operate 17)division 18)production 19)educate 20)repeat 1) additional 2) add 3) addition 4) addition 1) effectively 2) effect 3) effective 4) effect 1) helpful 2) help 3) helpless 4) help 5) helplessly 6) helpfully 7) helpful 1) reliant 2) reliable 3) reliance reliable 4) relies 5) reliably 6) 1) repetition 2) repeating 3) repeatedly 4) repeated 5) repetition 1) In my opinion 2) According to Mary 3) In our opinion 4) According to today's papers 5) In most doctors' opinion According to most doctors 1) Shakespeare was not only a dramatist but also an actor. 2) Miss Crain not only took me home in her car, but also came the next day to see if I had recovered. 3) Hainan Island attracts tourists not only in winter but also in summer.

大学英语精读3课后答案

大学英语精读3课后答案【篇一:大学英语精读第三版第三册课后答案(含 close原文)】 >1) accent 2) turn against 3) a couple of 4) takes his time 5) fate 6) confirmed 7) witness 8) subsequent 9) stands a chance 10) trial 1) belief 2) brilliant 3) employment 4) has saved up 5) stood a chance 6) were awarded 7) presumably 8) conducted 9) casual 10) around (which student life) revolves 1) joe wrote to say that he had to put off his visit because of his illness. 2) despite the noise, they went on working as if nothing were happening. 3) traffic was held up for several hours by the accident. 4) called (up) on to speak at the meeting, i couldnt very well refuse. 5) mrs. stevenson looked in the cupboard and found there was not a single lump of sugar left. 6) it was the rumor that turned joe against his twin brother. 7) we wondered how sara was getting on in her new job. 8) although anne agreed with me on most points, there was one on which she was unwilling to give in. 9) visitors could photograph almost anything here without having to ask for permission.

大学英语精读5_课后答案

U1 Vocabulary work 一1. given2. at a glance3. fluency4. Given5. hopefully6. For its part7. define8. looked him up9. no good10. quoted, context11. guidance12. immedi ate13. disgust14. come across15. put into practice16. scope 二 1. washed his hands of2. given3. putting… into practice4. was confronted with5. countering6. were reduced to eating7. at a glance8. took refuge in9. less practicable10. countered11. dedication12. in disgust13. relied on 14. for their part15. gave up 三 1. Without suitable entertainment, these young people often get bored and take refuge in drinking and taking drugs. 2. The school washed its hands of the students’ behavior during the spring recess. 3. The innocent girl was reduced to crying at his cruel remarks. 4. Many difficult words are out of the scope of his learner’s dictionary. 5. The thief admitted his guilt as soon as he was confronted with evidence. 6. The incident should be viewed in the wider context of the political turmoil of that time. 四 1. has come down 2. came to 3. comes out 4. come up with 5. come in 6. came across 7. has come about 8. come off 9. come to 10. give up 11. was given back 12. gave away 13. gave out 14. give in 15. gives off/out cloze 1. express 2. both 3. intended 4. still 5. where 6. personal 7. of 8. them 9. make 10. before 11. still 12. before 13. fluent 14. while 15. enough 16. on 17. in 18. In 19. Find 20. Who 21. carefully 22. to 23. possible 24. make 25. depend 26. than 27. made 28. use

相关文档
最新文档