1、大学英语六级模拟试卷 106及答案与解析 一、 Part I Writing (30 minutes) 1 1. 目前很多父母在子女高中毕业前就送他们出国学习 2. 形成这种趋势的原因 3. 我对些的看法 Oversea Study at an Early Age 二、 Part II Reading Comprehension (Skimming and Scanning) (15 minutes) Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the
2、questions attached to the passage. For questions 1-4, mark： Y (for YES) if the statement agrees with the information given in the passage; N (for NO) if the statement contradicts the information given in the passage; NG (for NOT GIVEN) if the information is not given in the passage. 2 Cable Televisi
3、on In the 1940s, there were four networks in the United States. Because of the frequencies allotted to television, the signals could only be received in a “line of sight“ from the transmitting antenna. People living in remote areas couldnt see the programs that were already becoming an important par
4、t of U. S. culture. In 1948, people living in remote valleys in Pennsylvania solved their reception problems by putting antennas on hills and running cables to their houses. These days, the same technology once used by remote villages and select cities allows viewers all over the country to access a
5、 wide variety of programs and channels that meet their individual needs and desires. By the early 1990s, cable television had reached nearly half the homes in the United States. Today, U. S. cable systems deliver hundreds of channels to some 60 million homes, while also providing a growing number of
6、 people with high-speed Internet access. Some cable systems even let you make telephone calls and receive new programming technologies! The earliest cable systems were, in effect, strategically placed antennas with very long cables connecting them to subscribers television sets. Because the signal f
7、rom the antenna became Weaker as it traveled through the length of cable, cable providers had to insert amplifiers at regular intervals to boost the strength of the signal and make it acceptable for viewing. “In a cable system, the signal might have gone through 30 or 40 amplifiers before reaching y
8、our house, one every 1,000 feet or so,“ Wall says, “With each amplifier, you would get noise and distortion. Plus, if one of the amplifiers failed, you lost the picture. Cable got a reputation for not having the best quality picture and for not being reliable.“ In the late 1970s, cable television wo
9、uld find a solution to the amplifier problem. By then, they had also developed technology that allowed them to add more programming to cable service. In the early 1950s, cable systems began experimenting with ways to use microwave transmitting and receiving towers to capture the signals from distant
10、 stations. In some cases, this made television available to people who lived outside the range of standard broadcasts. In other cases, especially in the northeastern United States, it meant that cable customers might have access to several broadcast stations of the same network. For the first time,
11、cable was used to enrich television viewing, not just make ordinary viewing possible. The addition of community antenna television stations and the spread of cable systems ultimately led manufacturers to add a switch to most new television sets. People could set their televisions to tune to channels
12、, or they could set them for the plan used by most cable systems. In both tuning systems, each television station was given a 6-megahertz (MHz) slice of the radio spectrum. The FCC (Federal Communications Commission) had originally devoted parts of the very high frequency (VHF) spectrum to 12 televi
13、sion channels. The channels werent put into a single block of frequencies, but were instead broken into two groups to avoid interfering with existing services. Later, when the growing popularity of television necessitated additional channels, the FCC allocated frequencies in the ultra-high frequency
14、 (UHF) portion of the spectrum. They established channels 14 to 69 using a block of frequencies between 470 MHz and 812 MHz. Because they used cable instead of antennas, cable television systems didnt have to worry about existing services. Engineers could use the mid-band, those frequencies passed o
15、ver by broadcast TV due to other signals, for channels 14-22. Channels 1 through 6 are at lower frequencies and the rest are higher. The “CATV Antenna“ switch tells the televisions tuner whether to tune around the mid-band or to tune straight through it. While were on the subject of tuning, its wort
16、h considering why CATV systems dont use the same frequencies for stations broadcasting on channels 1 to 6 that those stations use to broadcast over the airwaves. Cable equipment is designed to shield the signals carded on the cable from outside interference, and televisions are designed to accept si
17、gnals only from the point of connection to the cable or antenna; but interference can still enter the system, especially at connectors. When the interference comes from the same channel thats carded on the cable, there is a problem because of the difference in broadcast speed between the two signals
18、. Radio signals travel through the air at a speed very close to the speed of light. In a coaxial (同轴的 ) cable that brings CATV signals to your house, radio signals travel at about two-thirds the speed of light. When the broadcast and cable signals get to the television tuner a fraction of a second a
19、part, you see a double image called “ghosting“. In 1972, a cable system in Wilkes-Barre, PA, began offering the first “pay-per-view“ channel. The customers would pay to watch individual movies or sporting events. They called the new service Home Box Office, or HBO. It continued as a regional service
20、 until 1975, when HBO began transmitting a signal to a in geosynchronous (与地球的相对位置不变的 ) orbit and then down to cable systems. These early satellites could receive and retransmit up to 24 channels. The cable systems receiving the signals used dish antennas 10 meters in diameter, with a separate dish
21、for each channel! As the number of program options grew, the bandwidth of cable systems also increased. Early systems operated at 200 MHz, allowing 33 channels. As technology progressed, the bandwidth increased to 300,400,500 and now 550 MHz, with the number of channels increasing to 91. Two additio
22、nal advances in technology - fiber optics and analog-to-digital conversion - improved features and broadcast quality while continuing to increase the number of channels available. In 1976, a new sort of cable system debuted. This system used fiber-optic cable for the trunk cables that carry signals
23、from the CATV head-end to neighborhoods. The head-end is where the cable system receives programming from various sources, assigns the programming to channels and retransmits it onto cables. By the late 1970s, fiber optics had progressed considerably and so were a cost. Effective means of carrying C
24、ATV signals over long distances. The great advantage of fiber-optic cable is that it doesnt suffer the same signal losses as coaxial cable, which eliminated the need for so many amplifiers. Another benefit that came from the move to fiber-optic cable was greater customization. Since a single fiber-o
25、ptic cable might serve 500 households, it became possible to target individual neighborhoods for messages and services. In 1989, General Instruments demonstrated that it was possible to convert an analog cable signal to digital and transmit it in a standard 6-MHz television channel. Using MPEG compr
26、ession, CATV systems installed today can transmit up to 10 channels of video in the 6-MHz bandwidth of a single analog channel. When combined with a 550-MHz overall bandwidth, this allows the possibility of nearly 1,000 channels of video on a system. In addition, digital technology allows for error
27、correction to ensure the quality of the received signal, also changed the quality of one of cable televisions most visible features: the scrambled channel. The first system to “scramble“ a channel on a cable system was demonstrated in 1971. In the first scrambling system, one of the signals used to
28、synchronize the television picture was removed when the signal was transmitted, then reinserted by a small device at the customers home. Later scrambling systems inserted a signal slightly offset from the channels frequency to interfere with the picture, then filtered the interfering signal out of t
29、he mix at the customers television. In both cases, the scrambled channel could generally be seen as a jagged, disarranged set of video images. In a digital system, the signal isnt scrambled, but encrypted (加密的 ). The signal must be decoded with the proper key. Without the key, the digital-to-analog
30、converter cant turn the stream of bits into anything usable by the televisions tuner. When a “non-signal“ is received, the cable system substitutes an advertisement or the familiar blue screen. 2 In 1948, people living in remote areas could see TV programs by _ in the United States. （ A） a “line of
31、sight“ （ B） transmitting antenna （ C） frequencies allotted to television （ D） putting antennas on hills and running cables to houses 3 In the United States, cable television had come to nearly fifty percent of the homes by _. （ A） 1948 （ B） 1940s （ C） 1970s （ D） 1990s 4 How did cable providers solve
32、 the problem of the earliest cable systems? （ A） They strategically placed antennas with very long cables connecting to subscribers television sets. （ B） They made the signal from the antenna travel through the length of cable. （ C） They inserted amplifiers at regular intervals. （ D） They increased
33、the length of cable. 5 Cable television had developed technology that allowed them to add more programming to cable service in _. （ A） In the early 1990s （ B） In the late 1970s （ C） In the early 1950s （ D） In the early 1940s 6 Whats the purpose of the manufacturers adding a switch to most new televi
34、sion sets? （ A） To make more money. （ B） To spread the cable system. （ C） To make ordinary viewing possible. （ D） To adapt to the new development of the cable system. 7 What do we know about the “ghosting“ from the passage? （ A） It is a double image of TV. （ B） It refers to the speed of light. （ C）
35、It was eventually solved by engineers. （ D） It refers to the speed of the radio signals. 8 As the bandwidth increased to 550 MHz, the number of TV channels increased by _compared with the early cable systems. （ A） 24 （ B） 33 （ C） 58 （ D） 91 9 Cable systems began tying to use _ to capture the signals
36、 from distant stations in the early 1950s. 10 In tuning system, the Federal Communications Commission had distributed parts of _ spectrum to 12 television channels which were broken into two groups to avoid interference with existing services at the beginning. 11 In a digital cable system, if there
37、is no key to decode the signal, then, we will only see _. Section A Directions: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, one or more questions will be asked about what was said. Both the conversation and the questions will be spo
38、ken only once. After each question there will be a pause. During the pause, you must read the four choices marked A, B, C and D, and decide which is the best answer. （ A） He thought the womans birthday was next week. （ B） The restaurant closes early during the week. （ C） The woman should find out if
39、 she can reserve a table. （ D） He wont be able to go with the woman. （ A） She needs more time to get ready for the dinner. （ B） She thought the dinner was at another time. （ C） She forgot about the plans she made for dinner. （ D） She wont be able to go to dinner. （ A） Linda didnt like it. （ B） Bill
40、lost it. （ C） It was very expensive. （ D） It was very small. （ A） She left the lecture for a few minutes. （ B） She was reading during the lecture. （ C） She may have fallen asleep. （ D） She misunderstood the speakers last points. （ A） 40 minutes. （ B） 50 minutes. （ C） 45 minutes. （ D） 55 minutes. （ A
41、） She decided to buy a gold necklace. （ B） She decided to buy a pair of gold earrings. （ C） She decided to buy a pair of gold earrings and necklace. （ D） She decides to buy a pair of silver earrings. （ A） During literature class. （ B） The next day. （ C） In about an hour. （ D） Before literature class
42、. （ A） Where the man heard the news. （ B） How the man feels about the news. （ C） If the man is going to lose his job. （ D） If the man is going to the company. （ A） Set up your own website. （ B） Consult the banks representatives. （ C） Try by making transfers. （ D） Cheek your statements. （ A） The pers
43、on who is addicted to the Internet. （ B） The person who reads every label of the goods. （ C） The person who wants to buy fruit. （ D） The person who is not picky. （ A） The famous brands, （ B） The cereals. （ C） Books. （ D） Meat. （ A） It is closing down some factories in the US. （ B） It no longer offer
44、s high-paying jobs. （ C） The number of its employees is doubled after the restructuring. （ D） It is manufacturing as many cars as before. （ A） Over 87,000 workers will lose their jobs in auto companies. （ B） Many people will have to say bye-bye to their high salaries. （ C） The employees laid-off has
45、 a great impact on the American business. （ D） America can no longer hake a lead in world economy. （ A） They produced more cars than American manufacturers. （ B） They reduced car-production in America. （ C） They gave up more market share to the natives. （ D） They took over plants and manufacturing c
46、apacity. （ A） It is a serious throat to its competitors. （ B） It is not powerful enough to affect the world market. （ C） The cars quality is good enough to have their own branding. （ D） None of the Chinese cars meet the standard in the US. Section B Directions: In this section, you will hear 3 short
47、 passages. At the end of each passage, you will hear some questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A, B, C and D. （ A） Light darkens silver salt. （ B） Light darkens natural salt. （
48、C） Light darkens silver. （ D） Light darkens self-developing film. （ A） A boom period of photography. （ B） The official date of the peak of photography. （ C） The official date of the beginning of photography. （ D） A meaningless year of photography. （ A） He was remembered because he was once a brave s
49、oldier. （ B） He was remembered because he took many war photographs. （ C） He was remembered because he painted great portraits. （ D） He was remembered because he designed a portable camera. （ A） Pollution problems. （ B） Water supplies around the world. （ C） An industrial site in Missouri. （ D） Groundwater pollution. （ A） There is a greater demand of clean water. （ B） More water sources are polluted or disappearing. （ C） Developed countries consume too much water. （ D） More water is ru
