[外语类试卷]大学英语四级模拟试卷192及答案与解析.doc
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1、大学英语四级模拟试卷 192及答案与解析 一、 Part I Writing (30 minutes) 1 For this part, you are allowed 30 minutes to write a composition on the topic Changes in College Students Ways of Spending Summer Vacation. Your composition should be based on the information given in table. You should write no less than 120 word
2、s according to the following outline: 1. State the changes briefly; 2. Give the possible reasons for the changes; 3. Predict the trend of changes. Ways 1990s 2000s Staying at home 55% 32% Traveling 16% 30% Doing social investigations 9% 28% Other ways 20% 10% 二、 Part II Reading Comprehension (Skimmi
3、ng 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 (for NO) if the statement contra
4、dicts the information given in the passage; NG (for NOT GIVEN) if the information is not given in the passage. 1 Naturalgas Vehicles Kermit the Frog once said, “Its not that easy being green.“ Although he wasnt referring to cars, his observation seems particularly appropriate for the auto industry t
5、oday: Designing, developing and marketing “green“ cars has not been an easy task, which is why gasolinepowered vehicles still rule the road and fossil fuels still ac count for almost 75 percent of the worlds energy consumption. As gasoline prices soar and concern over harmful emission mounts, how ev
6、er, cars that run on alternate fuel sources will become increasingly important. A naturalgas vehicle, or NGV, is the perfect example of such a carits fuelefficient, environmentally friendly and offers a relatively low cost of ownership. Natural Gas Basics The word “gas“ is a confusing term because i
7、t is used to de scribe many different substances that are similar hut not exactly the same. For example, the “gas“ you put in your car is gasoline, one component of crude oil, or petroleum. Petroleum is a dark, sticky liquid mixture of compounds formed underground by tile decay of ancient marine ani
8、mals. Natural gas also cranes from the decay of ancient organisms, but it naturally takes a gaseous form instead of a liquid form. Natural gas commonly occurs in association with crude oil. It is derived from both land plants and aquatic(水中的 ) organic matter and forms above or below oil deposits. It
9、 is often dissolved in crude oil at the high pressures existing in a reservoir. There are also reservoirs of natural gas, known as nonassociated gas, that contain only gas and no oil. Natural gas consists primarily of methane(甲烷 ) and other hydrocarbon gases. Hydrocarbons are organic compounds compo
10、sed only of the elements carbon and hydrogen. The hydrocarbons in natural gas are called saturated hydrocarbons because they contain hydrogen and carbon bound together by single bonds. Like gasoline, natural gas is combustible, which means it can be used in a combustion engine like gasoline. But car
11、s that could burn natural gas didnt appear on the scene until the 1930s. From Field to Ford We extract natural gas trapped in underground reservoirs by drilling wells into the earth. A modem well, equipped with diamondstudded drill bits, can drill to depths approaching 25,000 feet. Throughout the 19
12、th century, the use of natural gas remained localized because there was no way to transport large quantities of gas over long distances. In 1890, the invention of a leakproof pipeline coupling made it possible to transport gas miles from the source, Improvements in pipeline technology continued over
13、 the next two decades constructed more than 10 major natural gas transmission systems in the United States, making natural gas a viable energy source for many applications. The oil shortages of the late 1960s and early 1970s brought renewed interest in natural gas as a fuel source, especially for au
14、tomobiles. Today, owners of naturalgas vehicles can fill up their cars at one of 1,300 fueling stations located in the United States. Honda al so offers a personal natural gas pump to people who purchase its naturalgaspowered Civic. The pump uses a homes existing natural gas lines and can be install
15、ed for $500 to $1500. Naturalgas Vehicle Design Naturalgas vehicles use the same basic principles as gasoline powered vehicles. In other words, the fuel (natural gas in this case) is mixed with air in the cylinder of a fourstroke engine and then ignited by a spark plug to move a piston up and down.
16、Although there are some differences between natural gas and gasoline in terms of flammability and ignition temperatures, NGVs themselves operate on the same fundamental concepts as gasolinepowered vehicles. Still, some modifications are required to make an NGV work efficiently. These changes are pri
17、marily in the fuel storage tank, the engine and the chassis. Advantages The biggest advantage of NGVs is that they reduce environ mentally harmful emissions. Naturalgas vehicles can achieve up to a 93 percent reduction in carbon monoxide emissions, 33 percent reduction in emissions of various oxides
18、 of nitrogen and a 50 percent reduction in reactive hydrocarbons when compared to gasoline vehicles. NGVs also rate higher in particulate matter 10 (PM10) emissions. PM10 particles transport and deposit toxic materials through the air. NGVs that operate in diesel applications can reduce PM10 e missi
19、ons by a factor of 10. Naturalgas vehicles also offer these benefits: NGVs are safer. The fuel storage tanks on an NGV are thicker and stronger than gasoline or diesel (内燃机车 ) tanks. There has not been an NGV fueltank rupture in more than two years in the United States. Natural gas costs are lower t
20、han gasoline. On average, natural gas costs onethird less than gasoline at the pump. Natural gas is convenient and abundant. A weltestablished pipeline infrastructure exists in the United States to deliver natural gas to almost every urban area and most suburban areas. There are more than 1,300 NGV
21、fueling stations in the United States, and more are being added every day. Natural gas prices have exhibited significant stability compared to oil prices. Historically, natural gas prices have exhibited significant price stability compared to the prices of petroleumbased fuels. This stability makes
22、it easier to plan accurately for longterm costs. NGVs have lower maintenance costs. Because natural gas burns so cleanly, it results in less wear and tear on the engine and extends the time between tuneups and oil changes. Disadvantages One of the biggest complaints about NGVs is that they arent as
23、roomy as gasoline cars. This is because NGVs have to give up precious cargo and trunk space to accommodate the fuel storage cylinders. Not only that, these cylinders can be expensive to design and builda contributing factor to the higher overall costs of a naturalgas vehicle compared to a gasolinepo
24、wered car. Another drawback is the limited driving range of NGVs, which is typically about half that of a gasolinepowered vehicle. For example, Hondas natural gas Civic, the Civic GX, can go up to 220 miles without refueling. A typical gasolinepowered Civic can go approximately 350 miles without ref
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- 外语类 试卷 大学 英语四 模拟 192 答案 解析 DOC
