1、大学英语四级模拟试卷 93及答案与解析 一、 Part I Writing (30 minutes) 1 For this part, you are allowed 30 minutes to write a letter of thanks. You should write at least 120 words, and base your composition on the outline given below in Chinese: 假设你过生日时收到了 Lucy让人送来的鲜花 ，写信向她表示感谢。信的内容应包括： 1表达感谢之意 2提出回报对方 3期待对方做客 二、 Part
2、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 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
3、(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 Wildfires In just seconds, a spark or even the suns heat alone sets off an extremely large fire. The wildfire quickly spreads, consuming the thick, dried-o
4、ut plants and almost everything else in its path. What was once a forest becomes a virtual powder keg of untapped fuel. In a seemingly instantaneous burst, the wildfire overtakes thousands of acres of surrounding land, threatening the homes and lives of many in the vicinity. Fire Starters On a hot s
5、ummer day, when drought conditions peak, something as small as a spark from a train cars wheel striking the track can ignite a raging wildfire. Sometimes, fires occur naturally, ignited by heat from the sun or a lightning strike. However, the majority of Wildfires are the result of human carelessnes
6、s. Common causes for wildfires include: Arson Campfires Discarding lit cigarettes Improperly burning debris Playing with matches or fireworks Prescribed fires Everything has a temperature at which it will burst into flames. This temperature is called a materials flash point. Woods flash point is 572
7、 degrees Fahrenheit(300 ). When wood is heated to this temperature, it releases hydrocarbon gases that mix with oxygen in the air, combust and create fire. There are three components needed for ignition and combustion to occur. A fire requires fuel to burn, air to supply oxygen, and a heat source to
8、 bring the fuel Up to ignition temperature. Heat, oxygen and fuel form the fire triangle. Firefighters often talk about the fire triangle when they are trying to put out a blaze. The idea is that if they can take away any one of the pillars of the triangle, they can control and ultimately extinguish
9、 the fire. After combustion occurs and a fire begins to burn, there are several factors that determine how the fire spreads. These three factors include fuel, weather and topography. Depending on these factors, a fire can quickly fizzle or turn into a raging blaze that scorches thousands of acres. F
10、ueling the Flames Wildfires spread based on the type and quantity of fuel that surrounds it. Fuel can include everything from trees, underbrush and dry grassy fields to homes. The amount of flammable material that surrounds a fire is referred to as the fuel load. Fuel load is measured by the amount
11、of available fuel per unit area, usually tons per acre. A small fuel load will cause a fire to burn and spread slowly, with a low intensity. If there is a lot of fuel, the fire will burn more intensely, causing it to spread faster. The faster it heats up the material around it, the faster those mate
12、rials can ignite. The dryness of the fuel can also affect the behavior of the fire. When the fuel is very dry, it is consumed much faster and creates a fire that is much more difficult to contain. Here are the basic fuel characteristics that decide how it affects a fire: Size and shape Arrangement M
13、oisture content Small fuel materials, also called flashy fuels, such as dry grass, pine needles, dry leaves, twigs and other dead brush, burn faster than large logs or stumps(this is why you start a fire with kindling rather than logs). On a chemical level, different fuel materials take longer to ig
14、nite than others. But in a wildfire, where most of the fuel is made of the same sort of material, the main variable in ignition time is the ratio of the fuels total surface area to its volume. Since a twigs surface area is much larger than its volume, it ignites quickly. By comparison, a trees surfa
15、ce area is much smaller than its volume, so it needs more time to heat up before it ignites. As the fire progresses, it dries out the material just beyond it heat and smoke approaching potential fuel causes the fuels moisture to evaporate. This makes the fuel easier to ignite when the fire finally r
16、eaches it. Fuels that are somewhat spaced out will also dry out faster than fuels that are packed tightly together, because more oxygen is available to the thinned-out fuel. More tightly-packed fuels also retain more moisture, which absorbs the fires heat. Wind and Rain Weather plays a major role in
17、 the birth, growth and death of a wildfire. Drought leads to extremely favorable conditions for wildfires, and winds aid a wildfires progressweather can spur the fire to move faster and engulf more land. It can also make the job of fighting the fire even more difficult. There are three weather ingre
18、dients that can affect wildfires: Temperature Wind Moisture As mentioned before, temperature has a direct effect on the sparking of wildfires, because heat is one of the three pillars of the fire triangle. The sticks, trees and underbrush on the ground receive radiant heat from the sun, which heats
19、and dries potential fuels. Warmer temperatures allow for fuels to ignite and burn faster, adding to the rate at which a wildfire spreads. For this reason, wildfires tend to rage in the afternoon, when temperatures are at their hottest. Wind probably has the biggest impact on a wildfires behavior. It
20、s also the most unpredictable factor. Winds supply the fire with additional oxygen, further dry potential fuel and push the fire across the land at a faster rate. The stronger the wind blows, the faster the fire spreads. The fire generates winds of its own that are as many as 10 times faster than th
21、e wind of surrounding area. It can even throw embers into the air and create additional fires, an occurrence called spotting. Wind can also change the direction of the fire, and gusts can raise the fire into the trees, creating a crown fire. While wind can help the fire to spread, moisture works aga
22、inst the fire. Moisture, in the form of humidity and precipitation, can slow the fire down and reduce its intensity. Potential fuels can be hard to ignite if they have high levels of moisture, because the moisture absorbs the fires heat. When the humidity is low, meaning that there is a low amount o
23、f water vapor in the air, wildfires are more likely to start. The higher the humidity, the less likely the fuel is to dry and ignite. Since moisture can lower the chances of a wildfire igniting, precipitation has a direct impact on fire prevention, when the air becomes saturated with moisture, it re
24、leases the moisture in the form of rain. Rain and other precipitation raise the amount of moisture in fuels, which suppresses any potential wildfires from breaking out. Fire on the Mountain The third big influence on wildfire behavior is the lay of the land, or topography. Although it remains virtua
25、lly unchanged, unlike fuel and weather, topography can either aid or hinder wildfire progression. The most important factor in topography as it relates to wildfire is slope. Unlike humans, fires usually travel uphill much faster than downhill. The steeper the slope, the faster the fire travels. Fire
26、s travel in the direction of the ambient wind, which usually flows uphill. Additionally, the fire is able to preheat the fuel further up the hill because the smoke and heat are rising in that direction. Conversely, once the fire has reached the top of a hill, it must struggle to come back down becau
27、se it is not able to preheat the downhill fuel as well as the uphill. In addition to the damage that fires cause as they burn, they can also leave behind disastrous problems, the effects of which might not be felt for months after the fire burns out. When fires destroy all the vegetation on a hill o
28、r mountain, it can also weaken the organic material it the soil and prevent water from penetrating the soil. One problem that results from this is extremely dangerous erosion that can lead to debris flows. While we often look at wildfires as being destructive, many wildfires are actually beneficial.
29、 Some wildfires burn the underbrush of a forest, which can prevent a larger fire that might result if the brush were allowed to accumulate for a long time. Wildfires can also benefit plant growth by reducing disease spread, releasing nutrients from burned plants into the ground and encouraging new g
30、rowth. 2 This passage explores how wildfires are born and live. （ A） Y （ B） N （ C） NG 3 Wood will burst into flames at 300 degrees Fahrenheit. （ A） Y （ B） N （ C） NG 4 Wildfires are mainly caused by people, not by nature. （ A） Y （ B） N （ C） NG 5 In most situations, we measure fuel load by tons per he
31、ctare. （ A） Y （ B） N （ C） NG 6 The winds generated by the fire itself are a little slower than the wind of the surrounding area. （ A） Y （ B） N （ C） NG 7 Fires are like humans in that they usually travel downhill much faster than uphill. （ A） Y （ B） N （ C） NG 8 In fact, the effects of fires might not
32、 be felt for months. （ A） Y （ B） N （ C） NG 9 There are three components needed for ignition and combustion to occur: fuel, air and _. 10 In a wildfire, the main variable in ignition time is the ratio of the fuels total surface area _. 11 As far as a fires behavior is concerned, the most unpredictabl
33、e factor is _. 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
34、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） In the fields. （ B） At the market. （ C） In a plant garden. （ D） In a classroom. （ A） His car turned over in an accident. （ B） He had a slight traffic accident. （ C） His car
35、 was entirely damaged. （ D） He got injured in an accident. （ A） He tells her not to visit his class. （ B） The class objects to her visit. （ C） He tells her to visit his class next Monday. （ D） The class will have the examination next Monday. （ A） He approves of the action. （ B） He feels sorry for th
36、ose students. （ C） He considers the punishment excessive. （ D） He has no opinion about the action. （ A） He shouldnt cry whenever the baby cries. （ B） He cant tear the babys toy into pieces. （ C） He cant have pieces of cakes every time. （ D） He shouldnt be so nervous whenever the baby cries. （ A） He
37、takes a year off to work. （ B） He talks to the tutor about his problem. （ C） He works as a tutor to pay his tuition. （ D） He works on improving his language skills. （ A） She doesnt want her boyfriend to give her a car. （ B） Her boyfriend has a lot of money. （ C） The man ought to lend some money to h
38、er boyfriend. （ D） Her boyfriend was making fun of the man. （ A） Its important to work out a detailed plan first. （ B） They should apply for the money immediately. （ C） He doesnt know anything about what the woman is saying. （ D） He agrees with the woman completely. （ A） The hotel confused him with
39、another guest. （ B） Rooms are overbooked for that evening. （ C） There are no more rooms available for five people. （ D） The price for the room is more than he expected. （ A） A marathon. （ B） An outdoor music festival. （ C） A conference. （ D） A building renovation. （ A） He thinks it will take a long
40、time for him to receive the free coupon for the room. （ B） He feels he should first receive an apology from the manager for what has happened. （ C） He suggests that the hotel should give guests an additional 15% discount in cases like his. （ D） He implies that he might not visit again because of the
41、 problems he has had. （ A） He managed the sales department. （ B） He gave seminars on the Internet. （ C） He worked in a computer company. （ D） He worked as a sales clerk. （ A） A computer game software. （ B） A web page authoring program. （ C） A kind of beverage. （ D） A kind of fresh fruit. （ A） She wi
42、ll call Mr. Taylor in the next few clays. （ B） She will talk over their discussion with others. （ C） She will not contact him for further consideration. （ D） She will keep in touch with him in a few days. （ A） A computer sales negotiation. （ B） A preliminary interview. （ C） An Internet seminar meeti
43、ng. （ D） A negotiation on the Net. 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 the best answer from the four ch
44、oices marked A, B, C and D. （ A） Because people dont know how to behave in social situations. （ B） Because most people are shy by nature. （ C） Because nobody will laugh at you for being shy. （ D） Because shyness is difficult to overcome. （ A） By prediction. （ B） By recording. （ C） By observation. （
45、D） By examination （ A） To observe peoples attitude towards strangers. （ B） To see how people get along with their friends. （ C） To test peoples behavior in social life. （ D） To find out how shy people are. （ A） Cheap clothes. （ B） Expensive clothes. （ C） Fashionable clothes. （ D） Informal clothes. （
46、 A） They enjoy loud music. （ B） They seldom lose their temper. （ C） They want to have children. （ D） They enjoy modem dances. （ A） Her twin sister often brings friends home and this annoys the speaker. （ B） They cant agree on the color of the room. （ C） They cant agree on the kind of furniture. （ D）
47、 The speaker likes to keep things neat while her twin sister doesnt. （ A） Power. （ B） Academic degree. （ C） Wealth. （ D） Diligence. （ A） The change of life-style. （ B） The change of the nature of occupations. （ C） The increase of social wealth. （ D） The increase of job opportunities. （ A） Politician
48、s. （ B） Clerks. （ C） Manual workers. （ D） Lawyers. （ A） Farm workers. （ B） White-collar workers. （ C） Blue-collar workers. （ D） Not mentioned. 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
49、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 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 Washington Irving was Americas first man of letters to be known internationally. His works were received 【 B1】 _ both in England and in the United Sta
