大学英语四级25及答案解析.doc

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1、大学英语四级 25 及答案解析(总分：746.57，做题时间：130 分钟)一、Writing (30 minutes)(总题数：1，分数：30.00)1.For this part, you are allowed 30 minutes to write an essay entitled On English Learning. You should write at least 120 words following the outline given below in Chinese: 1. 你认为在英语学习过程中存在的主要问题是什么？ 2. 导致这些问题的原因有哪些？ 3. 对于解决

2、这些问题，你有何建议？ （分数：30.00）_二、Reading Comprehensio(总题数：1，分数：71.00)Mobile phones What Are Mobile Phones? A mobile phone, also known as a cellphone or cellular phone, is a portable electronic device which behaves as a normal telephone whilst being able to move over a wide area (compare cordless phone which

3、 acts as a telephone only within a limited range). Cellphones allow connections to be made to the telephone network, normally by directly dialing the other partys number on an inbuilt keypad. Most current cellphones use a combination of radio wave transmission and conventional telephone circuit swit

4、ching, though packet switching is already in use for some parts of the cellphone network, especially for services such as Internet access and WAP. Some of the worlds largest cellphone manufacturers include Alcatel, Audiovox, Kyocera (formerly the handset division of Qualcomm), LG, Motorola, Nokia, P

5、anasonic (Matsushita Electric), Philips, Sagem, Samsung, Sanyo, Siemens, SK Teletech, and Sony Ericsson. There are also specialist communication systems related to, but distinct from cellphones, such as satellite phones and Professional Mobile Radio. Worldwide Deployment Cellphones have a long arid

6、varied history that stretches back to the 1950s, with hand held devices being available since 1983. Due to their low establishment costs and rapid deployment, cellphone networks have since spread rapidly throughout the world, outstrip ping the growth of fixed telephony. In most of Europe, wealthier

7、parts of Asia, Australia, and the US, cellphones are now widely used, with the majority of the adult, teenage, and even child population owning one. The number of cell phone subscribers in the US has reached over 190 million. The availability of Prepaid or pay as you go services, where the subscribe

8、r does not have to commit to a long term contract, has helped fuel this growth. Standardized Technology The cellphone has become ubiquitous because of the interoperability of cellphones across different networks 4nd countries. This is due to the equipment manufacturers all working to the same standa

9、rd, particularly the GSM standard which was designed for Europe-wide interoperability. All European nations and some Asian nations chose it as their sole standard, while in Japan and South Korea another standard, CDMA, was select ed. Cellphone Culture In less than twenty years, mobile phones have go

10、ne from being rare and expensive pieces of equipment used by businesses to a pervasive low-cost personal item. In many countries, cellphones now outnumber land line telephones, with most adults and many children now owning cellphones. It is not uncommon for young adults to simply own a cell phone in

11、stead of a land-line for their residence. In some developing countries, where there is little existing fixed-line infrastructure, the mobile phone has become widespread. Social Life With high levels of mobile telephone penetration, a mobile culture has evolved, where the phone becomes a key social t

12、ool, and people rely on their cellphone addressbook to keep in touch with their friends. Many people keep in touch using SMS, and a whole culture of “texting“ has developed from this. The commercial market in SMSs is growing. Many phones even offer Instant Messenger services to increase the simplici

13、ty and ease of texting on phones. Entertainment The mobile phone itself has also become a totemic and fashion object, with users deco rating, customizing, and accessorizing their cellphones to reflect their personality. Like wise, customized ringtones have been developed. Etiquette Cellphone etiquet

14、te has become an important issue with mobiles ringing at funerals, weddings, movies and plays. Users often speak at increased volume, with little regard for others nearby people. It has become common practice for places like libraries and movie theatres to ban the use of cell phones, sometimes even

15、installing jamming equipment to prevent them. Media Cameraphones and videophones that can capture video and take photographs are increasingly being used to cover breaking news. Stories like the London Bombings, the Boxing Day Tsunami and Hurricane Katrina have been reported on by cameraphone users o

16、n news sites like NowPublic and photosharing sites like Flickr. Cellphone Features Cellphones are often packed with features that offer users far more than just the capability to send text messages and make voice calls. These may include internet browsing, music (MP3)playback, personal organizers, e

17、mail, watch/alarm, built-in cameras, ring tones, security measures (e. g. pin codes), SIM blocks, games, radio, push to talk, infra red and blue-tooth connectivity, and call registers. Network Features Though cellphones vary significantly from provider to provider, and even nation to nation (most no

18、ticeably in North America), all cellphones must generally accomplish tile same tasks regardless. Cellphones must be connected to the system of land-line phones. Cellphones must also be able to connect with each other just as easily, even if the two phones are not from the same mobile service provide

19、r. Consequently, all cellphone systems are comprised of two components; the handset, and the tower. The handset is the portable, referred to as the mobile phone, cellphone or a smartphone. The tower is a high-yield radio tower that the cellphones direct their radio communications to in order to conn

20、ect to the network of telecommunications. It could also be a network of satellites. Network Working Process The Handset Handsets feature a low power transceiver that is typically designed to transmit voice and data, or analog audio only, up to a few kilometers under ideal situations to where the tow

21、er is located. The handset listens for an available tower. Once found, the handset in forms that tower of its own unique identifier, and alerts the cellphone network that it is ready and standing-by to receive telephone calls. It then periodically repeats this information to the tower, and seeks out

22、 new towers over the duration it is powered on. The Tower Towers are large structures that feature a series of high power radio transmitters de signed to broadcast their presence and availability, and relay communications to the mobile handsets. The tower features a much higher -powered radio transc

23、eiver array that allows it to provide a radio communications dialog with handsets dozens of kilometers away. The tower is connected to the landline telephone infrastructure by a high-capacity phone line, and may also be connected to a dedicated data line. The tower can then route calls between the m

24、obile handsets its serving, and telephone calls over the landline. Because the tower tracks and relays what mobile handsets it is servicing, it can inform the mobile network provider so that at any given time a call to a cellphone can quickly be traced to the :tower that is servicing that handset. T

25、he Data Stream Most cellphones dialog between the handset and the tower is comprised of a data stream of digitized audio. The technology driving this process can vary, and in nations with no standard or preference (such as the United States), many incompatible technologies exist. Not only do transmi

26、ssion standards potentially differ, but so do the radio frequencies. Some technologies include AMPS for analog, and TDMA, CDMA and GSM for digital communications. Though nations like the USA have generally avoided official standardization, most nations of the world have agreed upon the GSM data tran

27、smission protocol for cellphones, and a small range of possible frequencies that cellphones may operate on. Phones are classified based on the technology they use and the features they have. （分数：71.00）(1).The main difference between cordless phones and cellphones is that cordless phones can only ope

28、rate in a limited range. （分数：7.10）A.YB.NC.NG(2).Satellite phones and Professional Mobile Radios are a kind of cellphone. （分数：7.10）A.YB.NC.NG(3).Because cellphones are quick to deploy and cheap to establish, they have spread rapidly throughout the world. （分数：7.10）A.YB.NC.NG(4).Because American cellph

29、one users can choose either the prepaid service or pay as you go, cellphone subscribers have increased in number. （分数：7.10）A.YB.NC.NG(5).CDMA and GSM are the two main network services available in Australia. （分数：7.10）A.YB.NC.NG(6).Texting is uncommon in Asian countries. （分数：7.10）A.YB.NC.NG(7).Cellph

30、one etiquette has become increasingly more important. （分数：7.10）A.YB.NC.NG(8).Email, watch/alarm, built-in cameras, ringtones, and SIM blocks are all 1 of cellphones. （分数：7.10）填空项 1:_(9).Cellphones must not only be connected to the system of 1 but also must be able to connect with each other just as

31、easily, even if the two phones are not from the same mobile service provider. （分数：7.10）填空项 1:_(10).Although most nations around the world have agreed upon GSM data transmission protocol for cellphones, the US has avoided official 1. （分数：7.10）填空项 1:_三、Listening Comprehens(总题数：1，分数：15.00)A.He ate all

32、the food.B.He cleaned the refrigerator.C.He worked day and night.D.He had a big lunch.A.Hes playing sports.B.Hes watching sports games.C.Hes driving.D.Hes fighting.A.She didnt feel well.B.She went dancing earlier.C.She came down to go dancing.D.She got mad at the woman.A.$5.00B.$5.60C.$4.40D.$6.60A.

33、In a shipping company office.B.In Professor Bensons office.C.In a publishers office.D.In a university store.A.They will have to take a different bus.B.The trip is too dangerous.C.They will have to wait.D.There is a problem with the bus.A.A secretary.B.A novelist.C.A newspaperman.D.A businessman.A.In

34、 New York.B.In Boston.C.In Michigan.D.In Washington.四、Section B(总题数：2，分数：10.00)A.He didnt really enjoy it very much.B.He liked its story, but the music was awful.C.He enjoyed every minute of the movie.D.He was excited with the development of the story.A.The usher.B.The people sitting next.C.The peop

35、le sitting in front of him.D.The people standing in the back.A.The man was cutting jokes all the time.B.The woman was talking about her boss.C.The woman was making comments on the performance of the actress.D.The man was telling the woman the entire story of the movie.A.A policeman is interviewing a

36、 witness.B.A police sergeant is interrogating a culprit.C.They are having a discussion about a criminal case.D.They are holding a court investigation of a crime.A.A man.B.A woman.C.A man and a woman.D.Two men.A.In her early twenties.B.Between twenty-five and thirty.C.Over thirty.D.Under twenty.A.Gua

37、rding the coasts of the United States.B.Being part of the United States Navy.C.Guiding people along the coast.D.Protecting people from army attack.A.Enforcing laws controlling navigation, shipping, immigration and fishing.B.Enforcing laws affecting the privately - owned boats in the U. S.C.Searching

38、 for missing boats and rescuing people.D.Training people to good swimmers along the beach.A.17000B.1700C.70000D.7000A.dangerousB.hardC.excitingD.dullA.From three to five months.B.Three months.C.Five months.D.Four months.A.Watch traffic.B.Obey commands.C.Cross streets safely.D.Guard the door.A.Three

39、weeks.B.Two weeks.C.Four weeks.D.Five weeks.A.Taking notes.B.Oiling the gate.C.Singing high notes.D.Overcoming her weakness.A.He was attracted by Mrs Jones.B.He had heard a noise.C.He had run out of gas.D.His tyres were punctured.A.The tyres.B.Another car passing by.C.The brakes.D.Mrs Joness singing

40、.A.She was fond of singing.B.She lived in a small house.C.She was a shy person.D.She was not conscious of her weakness.六、Section C(总题数：1，分数：10.00)I am amazed at some of the statements made concerning Greg Louganiss decision not to (36) 1 the fact that he was HIV-positive. Although AIDS has been a (3

41、7) 2 word since the early 1980s, it appears that people still dont have a (38) 3 concerning the realities of the situation. Even though the ways of contracting HIV are well-known, the general public still seems to react with (39) 4 fear for their own well-being when (40) 5 with someone who they know

42、 is HIV-positive or has AIDS. But because people who know that they are HIV-positive are very (41) 6 of this fact, they certainly will take more (42) 7 in protecting other people than will the millions of walking time (43) 8 who dont know their HIV status. (44) 9. That means (45) 10. Education is th

43、e key to this very complicated issue. (46) 11.（分数：10.00）填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_七、Reading Comprehensio(总题数：2，分数：355.00)Whatever their chosen method, Americans bathe zealously. A study conducted found that we take an average of 4.5 baths and 7.5 sh

44、owers each week and in the ranks of non edible items purchased by store customers, bar soap ranks second, right after toilet paper. We spend more than $ 700 million annually on soaps, but all work the same way. Soap is composed of molecules that at one end attract water and at the other end attract

45、oil and dirt, while repelling water. With a kind of pushing and pulling action, the soap loosens the bonds holding dirt to the skin. Unless youre using a germicidal soap, it usually doesnt kill the bacteria soap simply removes bacteria along with dirt and oil. Neither baths nor showers are all that

46、necessary and unless youre in a Third World country where infectious diseases are common, or you have open sores on your skin, the dirt and bacteria arent going to hurt. The only reason for showering or bathing is to feel clean and refreshed. There is a physiological basis for this relaxed feeling.

47、Your limbs become slightly buoyant in bathwater, which takes a load off muscles and tension. Moreover, if the water is hotter than normal body temperature, the body attempts to shed heat by expanding the blood vessels near the surface of the skin, lessening the circulatory systems resistance to bloo

48、d flow, and dropping blood pres sure gently. A bath is also the most effective way to hydrate the skin. The longer you soak, the more water gets into the skin and because soap lowers the surface tension of the water, it helps you hydrate rapidly and remove dry skin flakes. However, in a bath, all the dirt and grime and the soap in which its suspended float on the surface. So when you stand up, it covers your body like a film. The real solution is to take a bath and then rinse off with a shower, however, after leaving a tub