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Propulsion engines and the vast majority of auxiliary generator engines are designed to al

low a generous through-flow of scavenge air in order to control ____.

A.the lubricating oil consumption

B.the turbine blade temperature

C.the flow rate of fuel

D.scavenge air pressure

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更多“Propulsion engines and the vas…”相关的问题
第1题
In gasoline engines()are used to ignite the fuel-air mixture,producing the power.

A.3-side rotor

B.gasoline

C.spark plugs

D.diesel

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第2题
Most larger main engines are arranged for continuous bypass purification using ().
Most larger main engines are arranged for continuous bypass purification using ().

A. settling

B. centrifugal purifiers

C. blending

D. heating

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第3题
For what reason is Titanic believed to be the safest ship ever?()

A.Titanic is equipped with three main engines—two reciprocating four-cylinder, triple-expansion steam engines

B.Titanic is said to be the most luxurious one ever floating in the ocean

C.Titanic has enough life boats for every passenger on board

D.Titanic has advanced safety features such as watertight compartments and remotely activated watertight doors

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第4题
听力原文:W: Hi, Mike.M: Hi. I'm surprised to see you on the city bus. Why not drive your c

听力原文:W: Hi, Mike.

M: Hi. I'm surprised to see you on the city bus. Why not drive your car?

W: (23)I've been thinking about the environment lately. If we all use public transportation when we could, the air will be much cleaner.

M: Right. But the bus isn't exactly pollution free.

W: True. But they'll be running a lot cleaner soon, We were just talking about that in my environmental engineering class.

M: What's the city going to do? Install pollution filters of some sort on their buses?

W: They could, but those filters make the engines work harder and really cut down on fuel efficiency. Instead they found a way to make their engines more efficient.

M: How?

W: Well, (24)there is a material called the coniine oxide. It's a really good insulator. And a thick coat of it gets sprayed on the certain part of the engine.

M: An insulator?

W: Yes. (25)It reflects back the heat of burning fuel. So the fuel will burn much hotter and burn up more completely.

M: So a lot less unburned fuel comes out to pollute the air, right?

W: Yeah, and the bus will need less fuel. So with the savings on fuel cost, they say this will all pay for itself in just six months.

M: Sounds like people should all go out and get this stuff to spray their car engines.

W: Well, not really that easy. To melt the materials before you can spray a coat of it on the engine parts, you first have to heat it over 10,000 degrees. It's not something we are able to do ourselves.

(20)

A.Something is wrong with her car.

B.The cost of the fuel is high.

C.It's cheap to take bus.

D.She thinks public transportation is environmental friendly.

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第5题
It looked just like another aircraft from the outside. The pilot told his young passengers
that it was built in 1964.But appearances were deceptive, and the 13 students from Europe and the USA who boarded the aircraft were in for the flight of their lives.

Inside, the area that normally had seats had become a long white tunnel. Heavily padded (填塞) from floor to ceiling, it looked a bit strange. There were almost no windows, but lights along the padded walls illuminated it. Most of the seats had been taken out, apart from a few at the back, where the young scientists quickly took their places with a look of fear.

For 12 months, science students from across the continents had competed to win a place on the flight at the invitation of the European Space Agency. The challenge had been to suggest imaginative experiments to be conducted in weightless conditions.

For the next two hours, the flight resembled that of an enormous bird which had lost its reason, shooting upwards towards the heavens before rushing .towards Earth. The invention was to achieve weightlessness for a few seconds.

The aircraft took off smoothly enough, but any feelings that I and the young scientists had that we were on anything like a scheduled passenger service were quickly dismissed when the pilot put the plane into a 45-degree climb which lasted around 20 seconds. Then the engines cut out and we became weightless. Everything became confused and left or right, up or down no longer had any meaning. After ten seconds of free-fall descent(下降) the pilot pulled the aircraft out of its nosedive. The return of gravity was less immediate than its loss, but was still sudden enough to ensure that some students came down with a bump.

Each time the pilot cut the engines and we became weightless, a new team conducted its experiment. First it was the Dutch who wanted to discover how it is that eats always land on their feet. Then the German team who conducted a successful experiment on a traditional building method to see if it could be used for building a future space station. The Americans had an idea to create solar sails that could be used by satellites.

After two hours of going up and down in the lane doing their experiments, the predominant feeling was one of excitement rather than sickness. Most of the students thought it was an unforgettable experience and one they would be keen to repeat.

What did the writer say about the plane?

A.It had no seats.

B.It was painted white.

C.It had no windows.

D.The outside was misleading.

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第6题
The rocket engine, with its steady roar like that of a waterfall or a thunderstorm, is
an impressive symbol of the new space age.Rocket engines have 11 powerful enough to shoot astronauts beyond the earth's gravitational pull and 12 them on the moon.We have now become travelers space.

Impressive and complex 13 it may appear, the rocket, which was invented in China over 800 years 14 , is a relatively simple device.Fuel that is burned in the rocket engine changes 15 gas.The hot and rapidly expanding gas must escape, but it can do so only 16 an opening that faces backward.As the gas is 17 with great force, it pushes the rocket in the 18 direction.Like the kick of a gun when it is fired, it 19 the laws of nature described by Sir Isaac Newton when he discovered that“ 20 every action, there is an equal and opposite reaction.”

11.A.shown

B.been

C.appeared

D.proved

12.A.send

B.land

C.take

D.carry

13.A.that

B.so

C.as

D.sometimes

14.A.in advance

B.before

C.earlier

D.ago

15.A.as

B.into

C.for

D.the

16.A.in

B.at

C.by

D.through

17.A.transmitted

B.dispersed

C.erected

D.radiated

18.A.same

B.other

C.opposite

D.wrong

19.A.states

B.proves

C.follows

D.breaks

20.A.like

B.as

C.with

D.for

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第7题
It was Ann' s first experience of flying. She had always been afraid of heights and so was
pre pared to be frightened. Only the fact that she was going to meet her son who she had not seen for three years had given her the courage to make the flight.

She sat in her seat, her hands gripping its arms, her seat belt already fastened. The air hostess was talking, telling everyone what to do in case of emergency, showing them where their .life-jackets were. The plane was crowded, every seat was full. From her window seat, getting out in a hurry would be impossible, thought Ann. In any case who would want to get out of a plane in mid-air?

The engines began to shake--the noise increased till it was like a great rushing wind. She looked out to see the runway slip past at astonishing speed. She wanted to cry out--to stop the plane before it left the ground, but she knew she was trapped in this great roaring machine. I must scream, she told herself, and put her hands over her eyes.

There was a strange feeling as if she were going up in a lift. The noise died down. Carefully she opened her eyes. Through the window she saw a great carpet of cloud above, so beautiful that she stared in wonder, hardly turning away from the window till they touched down.

Ann thought she would be frightened because ______.

A.she had never flown before

B.she had a fear of being in high places

C.she hadn' t made proper preparations.

D.she was naturally timid

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第8题
Cars account for half the oil consumed in the US, about half the urban pollution and one-f
ourth the greenhouse gases. They take a similar oil of resources in other industrial nations and in the cities of the developing world. As vehicle use continues to increase in the coming decade, the US and other countries will have to deal with these issues or else face unacceptable economic, health-related and political costs. It is unlikely that oil prices will remain at their current low level or that other nations will accept a large and growing US contribution to global climatic change.

Policymakers and industry have four options: reduce vehicle use, increase the efficiency and reduce the emissions of conventional gasoline-powered vehicles, switch to less harmful fuels, or find less polluting driving systems. The last of these -- in particular the introduction of vehicles powered by electricity -- is ultimately the only sustainable option. The other alternatives are attractive in theory but in practice are either impractical or offer only marginal improvements. For example, reduced vehicle use could solve traffic problems and a host of social and environmental problems, but evidence from around the world suggests that it is very difficult to make people give up their cars to any significant extent. In the US, mass transit ridership and carpooling have declined since World War Ⅱ. Even in western Europe, with fuel prices averaging more than $1 a liter (about $ 4 a gallon) and with easily accessible mass transit and dense populations, cars still account for 80 percent of all passenger travel.

Improved energy efficiency is also appealing, but automotive fuel economy has barely made any progress in 10 years. Alternative fuels such as natural gas, burned in internal-combustion engines, could be introduced at relatively low cost, but they would lead to only marginal reductions in pollution and greenhouse emissions (especially because oil companies are already spending billions of dollars every year to develop less polluting types of gasoline).

From the passage we know that the increased use of cars will ______.

A.consume half of the oil produced in the world

B.have serious consequences for the well-being of all nations

C.widen the gap between the developed and developing countries

D.impose an intolerable economic burden on residents of large cities

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第9题
2 Good Sports Limited is an independent sports goods retailer owned and operated by two pa
rtners, Alan and Bob. The

sports retailing business in the UK has undergone a major change over the past ten years. First of all the supply side

has been transformed by the emergence of a few global manufacturers of the core sports products, such as training

shoes and football shirts. This consolidation has made them increasingly unwilling to provide good service to the

independent sportswear retailers too small to buy in sufficiently large quantities. These independent retailers can stock

popular global brands, but have to order using the Internet and have no opportunity to meet the manufacturer’s sales

representatives. Secondly, UK’s sportswear retailing has undergone significant structural change with the rapid growth

of a small number of national retail chains with the buying power to offset the power of the global manufacturers.

These retail chains stock a limited range of high volume branded products and charge low prices the independent

retailer cannot hope to match.

Good Sports has survived by becoming a specialist niche retailer catering for less popular sports such as cricket,

hockey and rugby. They are able to offer the specialist advice and stock the goods that their customers want.

Increasingly since 2000 Good Sports has become aware of the growing impact of e-business in general and e-retailing

in particular. They employed a specialist website designer and created an online purchasing facility for their

customers. The results were less than impressive, with the Internet search engines not picking up the company

website. The seasonal nature of Good Sports’ business, together with the variations in sizes and colours needed to

meet an individual customer’s needs, meant that the sales volumes were insufficient to justify the costs of running

the site.

Bob, however, is convinced that developing an e-business strategy suited to the needs of the independent sports

retailer such as Good Sports will be key to business survival. He has been encouraged by the growing interest of

customers in other countries to the service and product range they offer. He is also aware of the need to integrate an

e-business strategy with their current marketing, which to date has been limited to the sponsorship of local sports

teams and advertisements taken in specialist sports magazines. Above all, he wants to avoid head-on competition

with the national retailers and their emphasis on popular branded sportswear sold at retail prices that are below the

cost price at which Good Sports can buy the goods.

Required:

(a) Provide the partners with a short report on the advantages and disadvantages to Good Sports of developing

an e-business strategy and the processes most likely to be affected by such a strategy. (12 marks)

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第10题
3 Airtite was set up in 2000 as a low cost airline operating from a number of regional air
ports in Europe. Using these

less popular airports was a much cheaper alternative to the major city airports and supported Airtite’s low cost service,

modelled on existing low cost competitors. These providers had effectively transformed air travel in Europe and, in so

doing, contributed to an unparalleled expansion in airline travel by both business and leisure passengers. Airtite used

one type of aircraft, tightly controlled staffing levels and costs, relied entirely on online bookings and achieved high

levels of capacity utilisation and punctuality. Its route network had grown each year and included new routes to some

of the 15 countries that had joined the EU in 2004. Airtite’s founder and Chief Executive, John Sykes, was an

aggressive businessman ever willing to challenge governments and competitors wherever they impeded his airline and

looking to generate positive publicity whenever possible.

John is now looking to develop a strategy which will secure Airtite’s growth and development over the next 10 years.

He can see a number of environmental trends emerging which could significantly affect the success or otherwise of

any developed strategy. 2006 had seen fuel costs continue to rise reflecting the continuing uncertainty over global

fuel supplies. Fuel costs currently account for 25% of Airtite’s operating costs. Conversely, the improving efficiency of

aircraft engines and the next generation of larger aircraft are increasing the operating efficiency of newer aircraft and

reducing harmful emissions. Concern with fuel also extends to pollution effects on global warming and climate

change. Co-ordinated global action on aircraft emissions cannot be ruled out, either in the form. of higher taxes on

pollution or limits on the growth in air travel. On the positive side European governments are anxious to continue to

support increased competition in air travel and to encourage low cost operators competing against the over-staffed

and loss-making national flag carriers.

The signals for future passenger demand are also confused. Much of the increased demand for low cost air travel to

date has come from increased leisure travel by families and retired people. However families are predicted to become

smaller and the population increasingly aged. In addition there are concerns over the ability of countries to support

the increasing number of one-parent families with limited incomes and an ageing population dependent on state

pensions. There is a distinct possibility of the retirement age being increased and governments demanding a higher

level of personal contribution towards an individual’s retirement pension. Such a change will have a significant impact

on an individual’s disposable income and with people working longer reduce the numbers able to enjoy leisure travel.

Finally, air travel will continue to reflect global economic activity and associated economic booms and slumps together

with global political instability in the shape of wars, terrorism and natural disasters.

John is uncertain as to how to take account of these conflicting trends in the development of Airtite’s 10-year strategy

and has asked for your advice.

Required:

(a) Using models where appropriate, provide John with an environmental analysis of the conditions affecting the

low cost air travel industry. (12 marks)

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第11题
The other problem that arises from the employment of women is that of the working wife. It
has two aspects: that of the wife who is more of a success than her husband and that of the wife who must rely heavily on her husband for help with domestic tasks. There are various ways in which the impact of the first difficulty can be reduced. Provided that husband and wife are not in the same or directly comparable lines of work, the harsh fact of her greater success can be obscured by a genial conspiracy to reject a purely monetary measure of achievement as intolerably crude. Where there are ranks, it is best if the couple work in different fields so that the husband can find some special reason for the superiority of the lowest figure in his to the most elevated in his wife's.

A problem that affects a much larger number of working wives is the need to re-allocate domestic tasks if there are children. In The Road to Wigan Pier George Orwell wrote of the unemployed of the Lancashire coalfields! "Practically never...in a working-class home, will you see the man doing a stroke of the housework. Unemployment has not changed this convention, which on the face of it seems a little unfair. The man is idle from morning to night but the woman is as busy as ever—more so, indeed, because she has to manage with less money. Yet so far as my experience goes the women do not protest. They feel that a man would lose his manhood if. merely because he was out of work, he developed in a 'Mary Ann'".

It is over the care of young children that this re-allocation of duties becomes really significant. For this, unlike the cooking of fish fingers or the making of beds, is an inescapably time-consuming occupation, and time is what the fully employed wife has no more to spare of than her husband.

The male initiative in courtship is a pretty indiscriminate affair, something that is tried on with any remotely plausible woman who comes within range and, of course, with all degrees of tentativeness. What decides the issue of whether a genuine courtship is going to get under way is the woman's response. If she shows interest the engines of persuasion are set in movement. The truth is that in courtship society gives women the real power while pretending to give it to men.

What does seem clear is that the more men and women are together, at work and away from it, the more the comprehensive amorousness of men towards women will have to go, despite all its past evolutionary services. For it is this that makes inferiority at work abrasive and, more indirectly, makes domestic work seem unmanly, if there is to be an equalizing redistribution of economic and domestic tasks between men and women there must be a compensating redistribution of the erotic initiative. If women will no longer let us beat them they must allow us to join them as the blushing recipients of flowers and chocolates.

Paragraph One advises the working wife who is more successful than her husband to______.

A.work in the same sort of job as her husband

B.play down her success, making it sound unimportant

C.stress how much the family gains from her high salary

D.introduce more labour-saving machinery into the home

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