[外语类试卷]大学英语四级模拟试卷21及答案与解析.doc

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1、大学英语四级模拟试卷 21及答案与解析 一、 Part I Writing (30 minutes) 1 For this part, you are allowed thirty minutes to write a letter. Imagine you are Wang Ting. Write a letter to Xiao Lin, a classmate of yours who is at home and suffering from eye strain(视疲劳 ). However, shes still willing to participate in the fort

2、hcoming CET-4 test. You should write no more than 120 words following the suggestions given below in Chinese. 1. 表示慰问 2. 告知有关你备考的情况 3. 提出你的建议 A Letter to a Classmate 二、 Part II Reading Comprehension (Skimming and Scanning) (15 minutes) Directions: In this part, you will have 15 minutes to go over th

3、e passage quickly and answer the questions attached to the passage. For questions 1-7, 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

4、 in the passage. 2 Creatures of the Thermal Vents(海底热泉区 ) The three-person submersible Alvin sank through the cold, dark waters of the Pacific Ocean for more than an hour, finally touching down on the sea floor more than 8,000 feet below the surface. It was December 1993, and the scientists inside t

5、he sub had come to this stretch of the East Pacific Rise, an underwater mountain range about 500 miles southwest of Acapulco, Mexico, to inspect a recently formed hydrothermal venta fissure(裂缝 ) in the ocean bottom that leaks scalding(滚烫的 ), acidic water. Peering out through the subs tiny windows, t

6、he visitors were astonished to see thickets of giant tube worms, some four feet tall. The tail ends of the worms were firmly planted on the ocean floor, while red plumes on the other ends swayed like a field of poppies. Alvin had brought researchers to the same spot less than two years earlier, when

7、 they had seen none of these strange creatures. Previous measurements showed that individual tube worms could increase in length at a rate of 33 inches per year, malting them the fastest-growing marine invertebrates. That means tube worms can grow more rapidly than scientists once thought. The giant

8、 tube worm is one of the most conspicuous members of a diverse community that forms around hydrothermal vents. Scientists once thought that no living thing could survive the harsh combination of toxic chemicals, high temperatures, high pressures, and total darkness at these vents. But in 1977, resea

9、rchers diving in Alvin discovered tube worms and other bizarre organisms thriving at a vent off the Galapagos Islands. Similar communities have since been found at several hundred hot spots around the world. These creatures are like nothing else on Earth. Vents form where the planets crystal plates

10、are slowly spreading apart and magma(岩浆 ) is welling up from below to form mountain ranges known as mid-ocean ridges. As cracks form at these spreading centers, seawater seeps a mile or two down into the hot rock. Enriched with minerals leached from the rock, the water heats and rises to the ocean f

11、loor to form a vent. Vents are usually clustered in fields, underwater versions of Yellowstones geyser(间歇泉 ) basins. Individual vent openings typically rage from less than a half inch to more than six feet in diameter. Such fields are normally found at a depth of more than a mile. Most have been dis

12、covered along the crest of the Mid-Oceanic Ridge, a 46,000-mile-long chain of mountains that wraps around Earth like the seams on a baseball. A few vents have also been found at seamounts(海底山 ), underwater volcanoes that are not located at the intersection of crystal plates. Hydrothermal vents provi

13、de habitat for many creatures that are not found anywhere else in the ocean. Water pouring out of vents can reach temperatures up to about 400 ; the high pressure keeps the water from boiling. However, the intense heat is limited to a small area. Within less than an inch of the vent opening, the wat

14、er temperature drops to 2 . Most of the creatures that congregate around vents live at temperatures just above freezing. Thus, chemicals are the key to vent life, not heat. The most prevalent chemical dissolved in vent water is hydrogen sulfide(硫化氢 ), which smells like rotten eggs. This chemical is

15、produced when seawater reacts with sulfate in the rocks below the ocean floor. Vent bacteria use hydrogen sulfide as their energy source instead of sunlight. The bacteria in turn sustain larger organisms in the vent community. The clams(蛤 ), mussels, tube worms, and other creatures at the vent have

16、a symbiotic relationship with bacteria. The giant tube worms, for example, have no digestive systemno mouth or gut. The worm depends virtually solely on the bacteria for its nutrition and both partners benefit. The brown, spongy tissue filling the inside of a tube worm is packed with bacteriaabout 2

17、85 billion bacteria per ounce of tissue. The plumes at the top of the worms body are red because they are filled with blood, which contains hemoglobin(血色素 ) that binds hydrogen sulfide and transports it to the bacteria housed inside the worm. In return, the bacteria oxidize the hydrogen sulfide and

18、convert carbon dioxide into carbon compounds that nourish the worm. Tube worms reproduce by spawning(产卵 ): They release sperm and eggs, which combine in the water to create a new worm. Biologists dont know how the infant worm acquires its own bacteria. Perhaps the egg comes with a starter set. Scien

19、tists also dont know how tube worms and other organisms locate new vents. The vents are small, and they are separated like islands. Most vent organisms have a free swimming larval stage. But scientists arent sure whether the larvae float aimlessly or purposely follow cluessuch as chemical traces in

20、the waterto find new homes. Studying the life cycle of vent organisms is difficult. Researchers have visited only a fraction(小部分 ) of the oceans hot spots. They have been able to observe vent life only by shining bright lights on creatures accustomed to inky darkness, and many specimens die quickly

21、when removed from their unique environment. Underwater cameras are helping scientists make less intrusive observations, but diving expeditions are still the most useful way to gather information. The 1993 Alvin expedition to the East Pacific Rise was one in a series of dives to the area. The site wa

22、s first visited in 1989, and scientists observed vent organisms thriving there. But when Alvin returned two years later, its occupants witnessed the birth of a hydrothermal vent. A recent volcanic eruption had spread glassy lava across the ocean floor, and the researchers measured temperatures up to

23、 403 the hottest ever recorded at a hydrothermal vent. “The most spectacular sight down there was this massive blinding snowstorm of bacteria,“ says Rich Lutz, a marine ecologist at Rutgers University, who led the expedition. On the ocean floor, the bacteria formed mats several inches thick, but the

24、 scientists saw no other living things. Since the eruption, scientists have been able to watch several stages of colonization at the site. When they returned in March 1992, only a few bacterial mats remained. In their place were colonies of Jericho worms and a variety of small crustaceans. In Decemb

25、er 1993, the scientists first observed the giant tube worms there. The scientists named the area Phoenix, because new life had arisen from the ashes of the eruption. 2 No living thing could survive at a vent except tube worms. （ A） Y （ B） N （ C） NG 3 Tube worms cant live in high-temperature environm

26、ent. （ A） Y （ B） N （ C） NG 4 It is chemicals that sustain vent life. （ A） Y （ B） N （ C） NG 5 The bacteria depend on worms for hydrogen sulfide in the symbiotic relationship. （ A） Y （ B） N （ C） NG 6 When a new vent forms, tube worms congregate around it voluntarily. （ A） Y （ B） N （ C） NG 7 Vent life

27、dies quickly when exposed to light. （ A） Y （ B） N （ C） NG 8 Before 1990, no giant tube worms were found in Phoenix. （ A） Y （ B） N （ C） NG 9 The majority of living things that gather around vents live at temperatures 10 Underwater cameras are helping scientists make _, but diving expeditions are stil

28、l the most useful way to gather information. 11 The scientists named the area Phoenix, because _ from the ashes of the eruption. 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 a

29、bout what was said. Both the conversation and the questions will be spoken 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） 1016. （ B） 1060. （ C） 508. （ D） 580. （ A） He is going to t

30、he hospital. （ B） He is showing his hand. （ C） He is letting her go. （ D） He is offering help. （ A） A shop assistant. （ B） A sales clerk. （ C） A waiter. （ D） A telephone operator. （ A） Father and daughter. （ B） Uncle and niece. （ C） Aunt and nephew. （ D） Cousins. （ A） She wasnt invited. （ B） She was

31、nt ready to come. （ C） She altered her decision. （ D） She forget the invitation. （ A） The door needs repairing. （ B） He had lost all his keys. （ C） He couldnt open the door. （ D） He wanted the woman to help him. （ A） Hes rather happy to hear so. （ B） Hes disappointed to hear so. （ C） Hes unhappy to

32、hear so. （ D） Hes surprised to hear so. （ A） He thought it was a good car. （ B） He thought it was too noisy. （ C） He thought there was wrong with the car. （ D） He didnt like it. （ A） They lived in caves. （ B） They traveled in groups. （ C） They had an advanced language. （ D） They ate mostly fruit. （

33、A） They lived in large groups. （ B） They used sand as insulation. （ C） They kept fires burning constantly. （ D） They faced their homes toward the sourth. （ A） Meet his anthropology teacher. （ B） Lend him her magazine when shes done with it. （ C） Come over to his house after class. （ D） Help him stud

34、y for an anthropology test. （ A） They may not be able to take their vacation. （ B） It may snow during their vacation. （ C） They me going to need more money. （ D） They may miss graduation. （ A） They are going skiing. （ B） Their plans include other friends. （ C） They will drive together. （ D） Their re

35、servations have been canceled. （ A） Because of the possibility of bad weather. （ B） Because of the facultys contracts. （ C） Because of the summer schedule of classes. （ D） Because of the date for graduation. （ A） He might lose his financial aid. （ B） He doesnt want to attend summer classes. （ C） He

36、had already missed too many. （ D） Hes afraid he might not graduate. Section B Directions: In this section, you will hear 3 short 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

37、 the best answer from the four choices marked A, B, C and D. （ A） The longest street in the world. （ B） A TV program. （ C） A country. （ D） The United States. （ A） Those who watch the show five times a week learn more than the occasional viewers. （ B） Those who watch the show occasionally learn more

38、than the five-time viewers. （ C） Those who watch the show at different hours learn more than regular viewers. （ D） Those who watch the show regularly learn more than the viewers watch it at different hours. （ A） The skillful use of a variety of TV tricks. （ B） The famous stars on “Sesame Street“. （

39、C） The children can learn and want to learn more. （ D） The children can understand. （ A） Because he wanted to be a great actor. （ B） Because he wanted to be a playwright. （ C） Because he was too poor to live on. （ D） Because he wanted to take care of horses. （ A） On foot. （ B） Riding horses. （ C） By

40、 carriage. （ D） Riding donkeys. （ A） When he was taking care of horses. （ B） When he was given an opportunity to play a part on the stage. （ C） When he began play-writing. （ D） When he had written many plays. （ A） A small town in Britain. （ B） A labor camp. （ C） A new type of jail. （ D） A big gymnas

41、ium in Scotland. （ A） Women criminals in Scotland. （ B） Criminals who are given long sentences. （ C） Criminals who are given short sentences. （ D） Criminals in Scotland. （ A） The reward the prisoners get for their work. （ B） The comfortable accommodation. （ C） The way the prisoners are treated. （ D）

42、 The officers sympathy for the prisoners. （ A） To give the prisoners more freedom. （ B） To help the prisoners keep their self- respect. （ C） To help the prisoners develop the sense of independence. （ D） To turn the prisoners into skilled- workers. Section C Directions: In this section, you will hear

43、 a passage three times. When the passage is read for the first time, you should listen carefully for its general idea. When the passage is read for the second time, you are required to fill in the blanks numbered from 36 to 43 with the exact words you have just heard. For blanks numbered from 44 to

44、46 you are required to fill in the missing information. For these blanks, you can either use the exact words you have just heard or write down the 37 In a competitive economy, the consumer usually has the choice of several different 【 B1】 _ of the same product. Yet underneath their labels, the produ

45、cts are often nearly 【 B2】 _. One manufacturers toothpaste 【 B3】 _ to differ very little from another manufacturers. Thus, manufacturers are 【 B4】 _ with a problemhow to keep sales high enough to stay in business. Manufacturers solve this problem by advertising. They try to appeal 【 B5】 _ to consume

46、rs in various ways. In fact, advertisements may be 【 B6】 _ into three types according to the kind of appeals they use. One type of advertisement tries to 【 B7】 _ to the consumers reasoning mind. It may offer a claim that seems scientific. For example it may say the dentists 【 B8】 _ flash toothpaste.

47、 In selling a product, 【 B9】 _. A scientific approach gives the appearance of truth. Another type of advertisement tries to amuse the potential buyer. 【 B10】 _. One way of doing this is to make the products appear alive. For example, the advertisers may personify cans of insecticide, and show them a

48、ttacking mean-faced bugs. Ads of this sort are silly, but they also tend to be amusing. 【 B11】 _. 37 【 B1】 38 【 B2】 39 【 B3】 40 【 B4】 41 【 B5】 42 【 B6】 43 【 B7】 44 【 B8】 45 【 B9】 46 【 B10】 47 【 B11】 Section A Directions: In this section, there is a passage with ten blanks. You are required to select

49、 one word for each blank from a list of choices given in a word bank following the passage. Read the passage through carefully before making your choices. Each choice in the bank is identified by a letter. Please mark the corresponding letter for each item with a single line through the center. You may not use any of the words in the bank more than once. 48 DINK, “Double Income No Kids“, 【 S1】 _ to families that consist of a husban