1、大学英语四级模拟试卷 129及答案与解析 一、 Part I Writing (30 minutes) 1 1. 据报道，我国南方多省市遭受严重冰冻雪灾； 2号召在校大学生捐款捐物； 3联系方式。 A Poster Calling for Donation 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 ques
2、tions 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 in the passage. 2 How Exercises Work
3、 When you exercise or compete in sports, you notice several things about your body. You breathe heavier and faster, your heart beats faster, your muscles hurt and you sweat. These are all normal responses to exercise whether you work out regularly or only once in a while or whether you are a “weeken
4、d warrior“ or a trained athlete. When you watch world-class athletes compete, you see the same responses, only magnified. The body bas an incredibly complex set of processes to meet the demands of working muscles. Every system in the body is involved. In this article, we will look at how your body r
5、esponds to strenuous exercise-how muscles, blood circulation, breathing and body heat are affected. You will also see how these responses can be enhanced by training. Your Bodys Response to Exercise Any type of exercise uses your muscles. Running, swimming, weightlifting-any sport you can imagine-us
6、es different muscle groups to generate motion. In running and swimming, your muscles are working to accelerate your body and keep it moving. In weightlifting, your muscles are working to move a weight. Exercise means muscle activity! As you use your muscles, they begin to make demands on the rest of
7、 the body. In strenuous exercise, just about every system in your body either focuses its efforts on helping the muscles do their work, or it shuts down. For example, your heart beats faster during strenuous exercise so that it can pump more blood to the muscles, and your stomach shuts down during s
8、trenuous exercise so that it does not waste energy that the muscles can use. When you exercise, your muscles act something like electric motors. Your muscles take in a source of energy and they use it to generate force. An electric motor uses electricity to supply its energy. Your muscles are bioche
9、mical motors, and they use a chemical called adenosine triphosphate (ATP) for their energy source. During the process of “burning“ ATP, your muscles need three things: They need oxygen, because chemical reactions require ATP and oxygen is consumed to produce ATP. They need to eliminate metabolic was
10、tes (carbon dioxide, lactic acid) that the chemical reactions generate. They need to get rid of heat. Just like an electric motor, a working muscle generates heat that it needs to get rid of. In order to continue exercising, your muscles must continuously make ATP. To make this happen, your body mus
11、t supply oxygen to the muscles and eliminate the waste products and heat. The more strenuous the exercise, the greater the demands of working muscle. If these needs are not met, then exercise will cease-that is, you become exhausted and you wont be able to keep going. To meet the needs of working mu
12、scle, the body has an orchestrated response involving the heart, blood vessels, nervous system, lungs, liver and skin. It really is an amazing system! Exercise and ATP For your muscles-in fact, for every cell in your body-the source Of energy that keeps everything going is called ATP. Adenosine trip
13、hosphate (ATP) is the biochemical way to store and use energy. The entire reaction that turns ATP into energy is a bit complicated, but here is a good summary: Chemically, ATP is an adenine nucleotide bound to three phosphates. There is a lot of energy stored in the bond between the second and third
14、 phosphate groups that can be used to fuel chemical reactions. When a cell needs energy, it breaks this bond to form adenosine diphosphate ( ADP ) and a free phosphate molecule. In some instances, the second phosphate group can also be broken to form adenosine monophosphate (AMP). When the cell has
15、excess energy, it stores this energy by forming ATP from ADP and phosphate. ATP is required for the biochemical reactions involved in any muscle contraction. As the work of the muscle increases, more and more ATP gets consumed and must be replaced in order for the muscle to keep moving. Because ATP
16、is so important, the body has several different systems to create ATP. These systems work together in phases. The interesting thing is that different forms of exercise use different systems, so a sprinter is getting ATP in a completely different way from a marathon runner! ATP comes from three diffe
17、rent biochemical systems in the muscle, in this order: phosphagen system glycogen-lactic acid system aerobic respiration Exercise and the Phosphagen System A muscle cell has some amount of ATP floating around that it can use immediately, but not very much-only enough to last for about three seconds.
18、 To replenish the ATP levels quickly, muscle cells contain a high-energy phosphate compound called creatine phosphate. The phosphate group is removed from creatine phosphate by an enzyme called creatine kinase, and is transferred to ADP to form ATP. The cell turns ATP into ADP, and the phosphagen ra
19、pidly turns the ADP back into ATP. As the muscle continues to work, the creatine phosphate levels begin to decrease. Together, the ATP levels and creatine phosphate levels are called the phosphagen system. Tile phosphagen system can supply the energy needs of working muscle at a high rate, but only
20、for 8 to l0 seconds. Exercise and the Glycogen-Lactic Acid System Muscles also have big reserves of a complex carbohydrate called glycogen. Glycogen is a chain of glucose molecules. A cell splits glycogen into glucose. Then the cell uses anaerobic metabolism (anaerobic means “without oxygen“) to mak
21、e ATP and a byproduct called lactic acid from the glucose. About 12 chemical reactions take place to make ATP under this process, so it supplies ATP at a slower rate than the phosphagen system. The system can still act rapidly and produce enough ATP to last about 90 seconds. This system does not nee
22、d oxygen, which is handy because it takes the heart and lungs some time to get their act together. It is also handy because the rapidly contracting muscle squeezes off its own blood vessels, depriving itself of oxygen-rich blood. There is a definite limit to anerobic respiration because of the lacti
23、c acid. The acid is what makes your muscles hurt. Lactic acid builds up in the muscle tissue and causes the fatigue and soreness you feel in your exercising muscles. Exercise and Aerobic Respiration By two minutes of exercise, the body responds to supply working muscles with oxygen. When oxygen is p
24、resent, glucose can be completely broken down into carbon dioxide and water in a process called aerobic respiration. The glucose can come from three different places: remaining glycogen supplies in the muscles; breakdown of the livers glycogen into glucose, which gets to working muscle through the b
25、loodstream; absorption of glucose from food in the intestine, which gets to working muscle through the bloodstream. Aerobic respiration can also use fatty acids from fat reserves in muscle and the body to produce ATP. In extreme cases (like starvation). proteins can also be broken down into amino ac
26、ids and used to make ATP. Aerobic respiration would use carbohydrates first, then fats and finally proteins, if necessary. Aerobic respiration takes even more chemical reactions to produce ATP than either of the above systems. Aerobic respiration produces ATP at the slowest rate of the three systems
27、, but it can continue to supply ATP for several hours or longer, so long as the fuel supply lasts. What Happens When You Exercise So imagine that you start running. Heres what happens: The muscle cells bum off the ATP they have floating around in about 3 seconds. The phosphagen system kicks in and s
28、upplies energy for 8 to 10 seconds. This would be the major energy system used by the muscles of a 100-meter sprinter or weight lifter, where rapid acceleration, short-duration exercise occurs. If exercise continues longer, then the glycogen-lactic acid system kicks in. This would be true for short-
29、distance exercises such as a 200- or 400-meter dash or 100-meter swim. Finally, if exercise continues, then aerobic respiration takes over. This would occur in endurance events such as an 800- meter dash, marathon run, rowing, cross-country skiing and distance skating. When you start to look closely
30、 at how the human body works, it is truly an amazing machine! 2 Your muscles are working to move a weight when you are _. （ A） swimming （ B） running （ C） weightlifting （ D） high jumping 3 During the process of “burning“ ATP, your muscles need _. （ A） to eliminate heat （ B） carbon dioxide （ C） lactic
31、 acid （ D） to add energy 4 When the cell has excess energy, it stores this energy by forming _. （ A） phosphate （ B） ADP （ C） AMP （ D） ATP 5 The body has several different systems to create _, because it is very important. （ A） AMP （ B） ATP （ C） ADP （ D） phosphate molecule 6 Muscle cells contain a hi
32、gh-energy phosphate compound called _. （ A） creatine kinase （ B） phosphate group （ C） creatine phosphate （ D） enzyme 7 What makes your muscles hurt? （ A） Glucose. （ B） Oxygen-rich blood. （ C） ATP. （ D） Lactic acid. 8 Glucose can be completely broken down into carbon dioxide and water when oxygen is
33、present in the process called _. （ A） anaerobic metabolism （ B） aerobic respiration （ C） burning ATP （ D） phosphagen system 9 When you are starving, proteins can also be broken down into 10 When you start running, the muscle cells burn off the ATP they have floating around in 11 Aerobic respiration
34、would occur in 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 spoken only once. After each question there wi
35、ll 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） They want to go downtown. （ B） He wants to go to the park, but she doesnt. （ C） He doesnt know where to park the car. （ D） He wants to find out where the park is. （ A） Comp
36、any and customer. （ B） Repairman and customer. （ C） Teacher and students parent. （ D） Wire and husband. （ A） She didnt like working in a company. （ B） She disliked machines. （ C） She was not good at doing business. （ D） She didnt like accounting. （ A） He has some money to buy a new car. （ B） He fail
37、s in borrowing enough money from the woman. （ C） He will spend much money on his house. （ D） He wants to buy a new house and a new cat. （ A） He had much trouble with his pronunciation. （ B） He began studying English too early. （ C） No one can understand him. （ D） He knew nothing about English. （ A）
38、Frustrated. （ B） Joyful. （ C） Excited. （ D） Sorry. （ A） He doesnt like that kind of food. （ B） The woman can do some cooking herself. （ C） He doesnt intend to buy them. （ D） The woman should stop looking at him. （ A） Mrs. Fisher wants to go abroad. （ B） Mrs. Fisher is in hospital. （ C） Mrs. Fisher h
39、as no family. （ D） There are three people in Mrs. Fishers family. （ A） Which major the woman will be choosing. （ B） An anthropology course the woman is taking. （ C） How to find a job in publishing. （ D） Which anthropology professors the man recommends. （ A） It is not as difficult as she had thought
40、it would be. （ B） She would like her professor to explain it more clearly, （ C） She took a class on it last semester. （ D） Her professor will write a book on it soon. （ A） Her professor. （ B） A classmate. （ C） Her former boss. （ D） A foreign diplomat. （ A） In the student recreation center. （ B） In t
41、he university bookstore. （ C） In the campus dining hall. （ D） In a classroom. （ A） Studying. （ B） Playing cards. （ C） Preparing snacks. （ D） Learning how to play bridge. （ A） Miss her card game. （ B） Take too heavy a work load next semester. （ C） Stay up too late. （ D） Neglect her studies to play br
42、idge. （ A） He already knows how to play. （ B） He doesnt have a partner. （ C） He doesnt like to play games. （ D） He doesnt have enough free time. 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 q
43、uestions 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） A new way to take notes. （ B） A short name for survey reading method. （ C） The five steps in the reading process. （ D） Different ways to study for examinatio
44、ns. （ A） That one should think about the ideas while reading the words. （ B） That one should always take notes. （ C） That one should read only the title and important words. （ D） That one should read sequences of words. （ A） Read. （ B） Recite. （ C） Review. （ D） Reread. （ A） Vacations. （ B） Wages. （
45、C） Overcrowded classrooms. （ D） Paid sick leaves. （ A） They want the teachers to resign. （ B） They want the teachers to return to work. （ C） They are very sympathetic toward the strike. （ D） They are refusing to comment on the situation. （ A） Parent Board. （ B） District Court. （ C） Teachers Union. （
46、 D） School Committee. （ A） Computers have become part of our daily lives. （ B） Computers have advantages as well as disadvantages. （ C） People have different attitudes to computers. （ D） More and more families will own computers. （ A） Computers can bring financial problems. （ B） Computers can bring
47、unemployment. （ C） Computers can be very useful in families. （ D） Computerized robots can take over some unpleasant jobs. （ A） Computers may change the life they have been accustomed to. （ B） Spending too much time on computers may spoil peoples relationship. （ C） Buying computers may cost a lot of
48、money. （ D） Computers may take over human beings altogether. （ A） Affectionate. （ B） Disapproving. （ C） Approving. （ D） Neutral. Section C Directions: In this section, you will hear a passage three times. When the passage is read for the first time, you should listen carefully for its general idea.
49、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 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 Building after building under water.【 B1】 in shelters. Thousands of others unsure where to go.【 B2】 for help. Anarchy. Bodies in streets. This is what one
