Sometimes during service the aircraft may ________ that may compromise the aircraft's safety.

A、farther from the runway than it actually is

B、the same distance from the runway as when there is no restriction to visibility

C、closer to the runway than it actually is

A、is descending

B、levels off

C、is ascending

The aircraft hijack situation is used in order to show that

A．the professionals do not pose much of a problem for the stores.

B．some people "simply forget to pay for what they take from the shops".

C．the honest public has to pay higher prices.

D．the third type of shop-lifters are dangerous people.

Because the aircraft industry needs ever-increasing quantities of aluminium plate, new equipment has been designed to automate the making of it. It includes a huge heat-treatment furnace, a crane that lifts hot metal plates without damaging them, and a computer system that can manage the complete flow of work.

Five years ago, Europe's aircraft industry needed only 8,000 tonnes of aluminium plate a year for its products. Last year the figure reached 21,800 tonnes. By 2004 it should total 30,000 tonnes. Each airliner contains 180 tonnes of it. That is why the plant is being rebuilt to increase both the quality and the amount of its product.

Aluminium is alloyed with other metals and cast into ingots, and the surface of the ingots is smoothed off. After pre-heating, it is rolled in a mill that can take 3.75-m-wide slabs. The new equipment can make the process more efficient and can produce a better product. For example, computers control the temperature of the hot plates, the rate at which they pass through the mill, the speed of cooling it with water, and so on.

The new plant can handle twice the throughput of the one that it is replacing, thanks to the completely automated and computerized process.

Certain portable electronic devices (PEDs) may interfere with aircraft navigational e quipment. PED use is permitted while on the ground when the boarding door is open, a nd in flight when advised by crew members. About 10 minutes before departure, passengers will be asked to turn off computers, cell phones and other PEDs. T he following PEDs are approved for use during the flight time: ？ Personal Computers ？ Handheld computer games ？ Personal stereo and video devices Medical devices are permitted at all times while TVs, radios, two-way radios, remote-control devices and some other electronic devices are not permitted. Due to safety concerns, the crew may at any time request that PEDs be turned off. Cell phones may be used only in the following instances: ？ When the aircraft is at the gate and the boarding door is open. ？ When the aircraft is on the ground away from the gate and the captain has approved their use.

What is the possible bad effect of using a PED on an aircraft in flight？ The aircraft navigational equipment may be ______.

Section B

Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A, B, C and D. You should decide on the best choice.

How would you design an aircraft if your main aim were to keep its roar from waking up the entire neighbor hood during takeoffs and landings? A group of 40 engineers from the Massachusetts Institute of Technology and England's University of Cambridge took on that challenge and, three years later, has unveiled designs for the SAX 40. Thanks to a host of noise-silencing innovations, the 215-seat airplane should be virtually inaudible outside the airport. Designers estimate that the aircraft will emit just 63 decibels(分贝) at takeoff, about as loud as an average conversation, while Today's airliners hit up to 150 decibels. However, when landing, it still is noisier than at take off, about 100 decibels.

To achieve such relative silence, researchers needed to rethink' nearly every aspect of the typical airliner. "There's no one thing you can do," says Will Graham, who headed up the Cambridge airframe-design team. "You have to treat all the noise sources."

What aspects should be considered? First, the long exhaust tubes have acoustic liners to get rid of noise, and the size of the exhaust nozzles can be made smaller during takeoff to reduce noise or larger while cruising for fuel efficiency. Second, instead of noisy flaps, a sloped wing and steep landing angle do the braking. Engines embedded in the frame, with air intakes an top, reduce drag and noise. Last, three radial-blade(径向叶片) fans per turbine move large volumes of air at low,quiet speeds. Precisely tuned turbine blades don't vibrate nonmoving parts.

Moreover, chief among the aspects is the airframe. The faster a plane flies, the louder it mars. So Graham and his group designed the SAX-40 with a blended-wing body, a concept that discard the tube-and-wing approach for a tailless, triangular structure. That shape provides extra lift, enabling the plane to fly more slowly during takeoffs and landings. It also saves a significant amount of fuel, getting some 35 percent more passenger-miles per gallon than a Boeing 777.

A number of other researchers are working on similar concepts. But challenges remain. An aircraft without a stabilizing tail would be far more difficult to fly. And then there is the question of how to make its flattened fuselage(机身) as structurally strong as a cylinder. But perhaps the biggest difficulty is the airline industry's financial in vestment in conservative design. Betting on such a radical plane, Graham says," would be a huge step for manufacturers."

What will be achieved by the design of SAX 40?

A．The noise SAX-40 made cannot be heard at take off.

B．The noise SAX-40 made cannot be heard during landings.

C．The noise SAX-40 made during landings will decrease sharply.

D．The noise SAX-40 made at takeoff will decrease sharply.

A.trace

B.trouble

C.destination

D.product

What did the aircraft carrier sail towards volatile waters for?

A．To carry out military exercises with South Korea.

B．To participate in the war.

C．To carry out military exercises with Japan.

D．To take part in a military show.

The opinion of many engineers is that the architects that designed tine New York World Trade Center Twin Towers did a good job in designing the buildings. The buildings were safe from the hazards envisioned at the time. Indeed, they were designed to withstand the force of aircraft that might crash into them. They were not, however, designed to withstand the effects of the very high temperatures generated by the ignition of tons of aviation fuel carried by the aircraft.

Steel lightly covered with concrete is the main structural component of the towers and steel loses a lot of structural strength when heated to 1,100 degrees Centigrade and beyond, as it was. To shield the steel the towers beams(柱梁) were c0ated with a few centimeters of concrete. That insulation was to provide structural integrity for at least 1 hour of fire. The towers met that test. The south tower lasted 62 minutes. The north, 103 minutes. Tragedy followed when not all could escape prior to the collapse.

Most experts agree that the Twin Towers were very. well designed. Many also agree that the pan pie planning the attacks were very knowledgeable and aimed the aircraft at a height that would effect the most damage. The aircraft crash and the resulting fuel fed fires were aimed at about the 90th floor. That was just high enough to insure that the upper floors would weaken with the heat and crack down, dropping into the remaining part of the building. The mass of the falling top floors created such a falling load that some experts estimate it exceeded by 5 to 10 times normal bearing loads. The effect was like a giant hammer, each floor contributing more weight to be born by the next floor down.

Were the Trade Towers well designed? Engineers say yes. But, the public refers to the belief that architects will never again design a tall building without considering the effects of terrorist attacks of all potential kinds. That not only includes the ability of the structure to withstand attack but the means to allow the buildings occupants(居住者) to escape in time to survive.

According to the article, those who designed the tower could have done better if ______.

A．the tower lasted longer after being attacked

B．the tower hold stable until all of the people there managed to escape

C．the tower can be immune to such attacks

D．they considered more about the effects of the very' high temperatures and make duel changes in the structure