Natural gas Vehicles Kermit the Frog once said, "It’’s not that easy bein’’green." Although he wasn’’t referring to cars, his observation seems particularly appropriate for the auto industry today: Designing, developing and marketing "green" cars has not been an easy task, which is why gasoline powered vehicles still rule the road and fossil fuels still account for almost 75 percent of the world’’s energy consumption. As gasoline prices soar and concern over harmful emission mounts, however, cars that run on alternate fuel sources will become increasingly important. A natural-gas vehicle, or NGV, is the perfect example of such a car―it’’s fuel-efficient, environmentally friendly and offers a relatively low cost of ownership. Natural Gas Basics The word "gas" is a confusing term because it is used to describe many different substances that are similar but 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 the decay of ancient marine animals. Natural gas also comes 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 (水生的) organic matter and forms above or below oil deposits. It is often dissolved in crude oil at the high pressures existing in a reservoir. There are also reservoirs of natural gas, known as non-associated gas, that contain only gas and no oil. Natural gas consists primarily of methane (沼气) and other hydrocarbon gases. Hydrocarbons are organic compounds composed 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 (易燃的), which means it can be used in a combustion engine like gasoline. But cars that could burn natural gas didn’’t 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 modern well, equipped with diamond-studded drill bits, can drill to depths approaching 25,000 feet. Throughout the 19th century, the use of natural gas remained localized because there was ho way to transport large quantities of gas over long distances. In 1890, the invention of a Teak-proof pipeline coupling made it possible to transport gas miles from the source. Improvements in pipeline technology continued over the next two decades until long-distance gas transmission became practical. From 1927 to 1931, laborers constructed more than 10 major natural gas transmission systems in the United States, making natural gas 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 automobiles! Today, owners of natural-gas vehicles can fill up their cars at one of 1,300 fueling stations located in the United States. Honda also offers a personal natural gas pump to people who purchase its natural-gas-powered Civic. The pump uses a home’’s existing natural gas lines and can be installed for 500 to 1500. Natural-gas Vehicle Design Natural-gas 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 four-stroke engine and then ignited by a spark plug to move a piston(活塞) up and down. 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 gasoline-powered vehicles. Still, some modifications are required to make an NGV work efficiently. These changes are primarily in the fuel storage tank, the engine and the chassis (底盘). Advantages The biggest advantage of NGVs is that they reduce environmentally harmful emissions. Natural-gas vehicles can achieve up to a 93 percent reduction in carbon monoxide emissions, 33 percent reduction in emissions of various oxides 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 emissions by a factor of 10. Natural-gas vehicles also offer these benefits: NGVs are safer. The fuel storage tanks on an NGV are thicker and stronger than gasoline or diesel tanks. There has not been an NGV fuel-tank rupture in more than two years in the United States. Natural gas costs are lower than gasoline. On average, natural gas costs one-third less than gasoline at the pump. Natural gas is convenient and abundant. A well-established 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 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 petroleum-based fuels. This stability makes it easier to plan accurately for long-term 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 tune-ups and oil changes. Disadvantages One of the biggest complaints about NGVs is that they aren’’t as 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 build―a contributing factor to the higher overall costs of a Natural-gas vehicle compared to a gasoline-powered car. Another drawback is the limited driving range of NGVs, which is typically about half that of a gasoline-powered vehicle. For example, Honda’’s natural gas Civic, the Civic GX, can go up to 220 miles without refueling. A typical gasoline-powered Civic can go approximately 350 miles without refueling. If a dedicated NGV ran out of fuel on the road, it would have to be towed to the owner’’s home or to a local natural gas refueling station, which might be harder to find than a "regular" gas station. Finally, it should be noted that natural gas, like gasoline, is a fossil fuel and cannot be considered a renewable resource. While natural gas reserves in the United States are still considerable, they are not inexhaustible. Some predict that there are enough natural gas reserves remaining to last another 67.1 years, assuming that the 2003 level of production continues.The basic principles applied to natural-gas vehicles are quite different from those applied to gasoline-powered vehicles. A．YB．NC．NG

King’s College Summer School is an annual(每年的) training program for all the middle school students who want to improve their English. Courses are given by the teachers of King’s College and other colleges in New York. Trips to museums and culture centers are also organized. This year’s summer school will be from June 1 to July 15. More information is as follows:Application (申请) date• Students in New York should send their applications before April 18, 2021•Students of other cities should send their applications before April 16, 2021• Foreign students should send their applications before April 10, 2021Courses•English LanguageSpoken English: 22 hoursReading and Writing: 10 hours•American History: 16 hours•American Culture: 16 hoursSteps•A letter of self-introduction•A letter of recommendation (推荐) from a teacher★The letters should be written in English with all the necessary information.Cost•Daily lessons: 200•Sports and activities: 100•Travels: 200•Hotel service: 400★You may choose to live with your friends or relatives in the same city.Please write to: Thompson Sanders1026 King’s StreetNew York, NY10016,USAEmail: KCSummerSchool@【小题1】You can most probably read the article in ________.A．a newspaperB．a travel guideC．a textbookD．a telephone book【小题2】According to the article, who will give the courses?A．The teachers of King’s College and the middle schools in America.B．The teachers of King’s College Summer School and other colleges in the United States.C．The teachers of the middle schools and Summer School in New York.D．The teachers of King’s College and other colleges in New York.【小题3】When should foreign students send their applications?A．Before April 10, 2021.B．Before June 1, 2021.C．Before April 16, 2021.D．Before July 15, 2021.

In order to process your returns, we are required to check both the condition of the goods and the integrity of your reason for returning them. After checking and approving your returns, we will promptly reimburse (赔付) the purchase price of the returned items. Reimbursements are made to the payment method used at the time of purchase.If you have received a faulty product or a wrong item and you inform us of the mistake and return the items within 14 days of receipt, we will refund you the costs in full, including all charges for postage.If goods are returned after the expiration (截止日期) of the 14 day revocation period (退货期), you carry the cost of returning the goods. This will be deducted from the amount we refund you for the returned items. Please understand that we cannot refund any shipping fees in this case.Reimbursement is normally processed within 14 days of receipt of returned goods. However, we ask for your understanding if the processing time during peak periods should take longer.Please note that your bank may take up to 10 working days to process your refund. This depends on the institution from which a payment card is issued and the respective processing time.36. What will be checked about your goods in order to process your returns?A) Their price.B) Their condition.C) Their shipping fees.D) Their manufacturers.37. How will the refund be paid for the returned items?A) Usually by credit card.B) By a mobile payment method.C) In most cases through an online payment.D) By the same method used at the time of purchase.38. You can get your refund in full only if you ________.A) buy the items within this countryB) agree to carry the cost of returningC) return the items within 14 days of receiptD) have a contract with the seller in advance39. During peak periods, the processing of your reimbursement may take ________.A) two daysB) ten daysC) no more than a weekD) longer than 14 days40. The word "deducted" in Paragraph 3 means ________.A) kept outB) turned onC) taken awayD) broken down

27. (2.0分) Complete projects must be _ by March.A. submergedB. substantiatedC. submittedD. subordinated

She started lifting weights to build .A. paintingB. mansionC. eventsD. muscle

No sooner had he arrived in Rome___ he heard of the good news.A. untilB. thenC. thanD. when

Dear Mr. Smith, I am writing to apply for the programmer position advertised in Jobs Now. As requested, I am now enclosing a completed job application, my résumé and three references. The role is very attractive to me, and I believe that my strong technical experience and education make me the best person for this position. My key strengths that would support my success in this position include: *I have successfully designed, developed and supported many software projects. *I always work hard for excellence(优秀). With a diploma in Computer Programming, I have a thorough understanding of the full lifecycle (生命周期) for software development projects. I am also capable of learning and applying new technologies. Please see my résumé for additional information on my experiences. I can be reached anytime by phone at 123-445-6767. Thank you for your time and consideration. I look forward to hearing from you soon. Sincerely, John DoeApplicant's Information Name: John Doe Position applied for: (48) Enclosure: a job application, a résumé and (49) Key strengths: 1)having designed, (50) many software projects. 2)always working hard for excellence Education: a (51) in Computer Programming Knowledge and skills: 1)understanding the full lifecycle for software development projects 2)being capable of (52) new technologies Contact: Tel. 123-445-6767

After leaving the theater, Mary ________ home.A. looked forB. applied forC. paid forD. headed for

The study notes a increase in the number of college students performing volunteer work.A. strategicB. steadyC. separate

句子结构分析: Kate's uncle lives in a village.A. 主系表B. 主谓C. 主谓宾D. 主谓宾宾E. 主谓宾宾补