air traffic is closely controlled, flying is relatively safe. [ ] A．UnlessB．As soon as C．AlthoughD．Once 题目和参考答案——青夏教育精英家教网—

题目内容

________ air traffic is closely controlled, flying is relatively safe.

[　　]

A．Unless

B．As soon as

C．Although

D．Once

答案：D
提示：

once意为“一旦”，引导时间状语从句。

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As motorways become more and more blocked up with traffic, a new generation on flying cars will be needed to ferry people along skyways. That is the conclusion of engineers from the US space agency and aeronautical firms, who envision future commuters traveling by “skycar”.

These could look much like the concept skycar shown in the picture, designed by Boeing research and development. However, such vehicles could be some 25 years from appearing on the market. Efforts to build flying vehicles in the past have not been very successful. Such vehicles would not only be expensive and require the skills of a trained pilot to fly, but there are significant engineering challenges involved in developing them. “When you try to combine them you get the worst of both worlds: a very heavy, slow, expensive vehicle that’s hard to use,” said Mark Moore, head of the personal air vehicle(PAV) division of the vehicle systems program at Nasa’s Langley Research Center in Hampton, US. But Boeing is also considering how to police the airways-and prevent total pandemonium(吵杂狂乱的喧闹)-if thousands of flying cars enter the skies.

“The neat, gee-whiz part is thinking about what the vehicle itself would look like,” said Dick Paul, a vice president with Phantom Works, Boeing’s research and development arm. “But we’re trying to think through all the consequences of what it would take to deploy(散开) a fleet of these.”

Past proposals to solve this problem have included artificial intelligence systems to prevent collisions between air traffic. Nasa is working on flying vehicles with the initial goal of transforming small plane travel. Small planes are generally costly, loud, and require months of training and lots of money to operate, making flying to work impractical for most people. But within five years, Nasa researchers hope to develop technology for a small plane that can fly out of regional airports, costs less than $100,000(??55,725), is as quiet as a motorcycle and as simple to operate as a car.

Although it would not have any road-driving capabilities, it would bring this form of travel within the grasp of a wider section of people. The new technology would automate many of the pilot’s functions. This Small Aircraft Transportation System(Sats) would divert pressure away from the “hub-and-spoke(中心辐射型)” model of air travel. Hub-and-spoke refers to the typically US model of passengers being processed through large “hub” airports and then on to secondary flights to “spoke” airports near their final destinations.

The best title for this text would be .

A. Developing Skycars B. The Traffic Jams in the Sky

C. How to Guide Flying Cars in the Sky D. What Flying Cars Will Look Like

The underlined word “envision” in Paragraph 1 most probably means “ ”.

A. see B. expect C. think D. announce

When engineers develop the skycars, they have to deal with the following difficulties except .

A. how to fly out of regional airports

B. how to prevent the disorder of the airways

C. how to reduce expenses and the vehicle’s weight

D. how to fly the skycars to enter skies

Now Nasa researchers’ aim is to .

A. make big flying cars

B. work out the plan——how to transform small plane travel

C. develop a new kind of small plane different from the traditional one

D. build a new kind of small plane with road-driving abilities

According to the air traffic rules, you______switch off your mobile phone before bearding.

A. may B. can C. would D. should

According to the air traffic rules, you ___ switch off your mobile phone before boarding.

B
(BBC News April 18) All flights in and out of the UK and several other European countries have been cancelled as ash from a volcanic eruption in Iceland moves south.
Up to 4,000 flights are being cancelled with airspace closed in Norway, Sweden, Finland and Denmark among others.
The UK’s air traffic control service (Nats) said no flights would be allowed in UK airspace until at least 07:00 BST on Friday for fear of engine damage.
Safety group Eurocontrol said the problem could last for 48 hours.
The volcano is still erupting and the wind direction is expected to continue bringing clouds into UK and European airspace for some time to come.
The UK’s airspace restriction was the worst in living memory, a Nats spokesman said. Some 600,000 people are thought to have been affected.
Nats suggested that the restrictions were unlikely to be lifted (解除) after 07:00, saying it was “very unlikely that the situation over England will improve in the foreseeable future”.
Passengers were advised to contact their carriers before travelling.
Transport Secretary Lord Adonis said he was “closely monitoring the situation” and would be meeting with key transport officials on Friday morning.
Experts have warned that the tiny particles of rock, glass and sand contained in the ash cloud from the still-erupting volcano could be sufficient to jam aircraft engines.
The Health Protection Agency said the ash from the eruption did not bring a significant risk to public health because of its high altitude.
However, the British Lung Foundation has warned people with lung conditions to keep their medication (医疗护理) with them as a precautionary measure.
These are some of the knock-on effects:
● Eurocontrol says Germany is monitoring the situation and considering partial airspace closures.
● The two main airports in Paris and many others in the north of France are closing.
● There is severe disruption (崩溃) in France and Spain, where all northbound flights are cancelled.
● Nats is due to make an announcement shortly as to the arrangements that will be in place
through to 13:00 BST on Friday.
● British Airways offers refunds or an option to rebook after all its domestic flights are suspended.
Flybe announces it has cancelled all flights up until 13:00 BST on Friday and more than 25 services due to run after that.
British sports teams have been hit by travel problems after flights were grounded.
60. What may passengers do on hearing the news according to the passage?
A. They may cancel their international flights.
B. They may contact the airlines before traveling.
C. They may take measures to protect their lungs from the ash.
D. They may stay indoors till the volcanic eruption dies down.
61. Why have some European countries cancelled flights after the volcanic eruption?
A. Because the volcanic ash may make passengers ill.
B. Because people refuse to take the international flights.
C. Because the volcanic ash may jam or damage the engine.
D. Because the flights may be hit by the rocks from the eruption.
62. Which of the following statements is true according to the passage?
A. All the flights are likely to return to normal in 48 hours.
B. British people had experienced a worse airspace restriction before that.
C. Germany is monitoring the situation and considering closing all airspace.
D. The UK airspace restrictions are unlikely to be lifted in the foreseeable future.

_____ ashes from the volcano in Iceland have caused problems for air traffic and business, scientists don't think it will have long-term effects on human health.

A．Since

B．As

C．While

D．Because

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