题目内容
Transportation
For many years in the desert, camels used to be the only form. of transportation(运输). Before the(51)of modern trains, camel trains used to carry all the goods for trading between Central Africa and Europe. Traders sometimes(52)to put together camel trains with 10,000 to 15,000 animals. Each animal often carried(53)400 pounds and could travel twenty miles a day. This form. of transportation was so important that camels were called the "ships of the(54)."
Now modern trains travel across the desert in a very(55)time. One engine can pull as much weight as 135,000(56), In addition, trains use special cars for their load. Refrigerator cars carry food; boxcars carry heavy goods, stock cars carry animals; and tank cars carry oil.
Air travel has changed, too. The earliest planes were biplanes (双翼飞机), with(57)sets of wings. The top speed of this plane was 60 miles per hour. The pilots used to sit or lie on the wings in the. open air. The plane(58)sometimes Stopped in the middle of a trip. it used to be(59)to fly in bad weather. In snow or in rain, the wings frequently became icy. Then the plane might go down.
Mechanical improvements during the First World War changed airplanes. Monoplanes(单翼飞机) took the(60)of biplanes. Pilots flew inside of covered cabins. Still, even these planes were small and expensive. Only(61)people were be able to travel in airplanes.
Now modern jets make air travel possible for all people. No place in the world is more than 24 hours away by jet. Further improvements have(62)the cost of flying, and they have made air travel(63)safer than it used to be. A modern 707 can carry 170 people and can fly at 600 miles per hour. People(64)used to eat, sleep, or watch movies on airplanes.(65)these things are a normal part of air travel!
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A．muchB．soC．veryD．such
Nonverbal Thinking in Engineering
Many objects in daily use have clearly been influenced by science. However, their form. and function, their dimensions and appearance, were determined by technologists, designers, inventors, and engineers using nonscientific modes of thought. Many features and qualities of the objects that a technologist thinks about cannot be reduced to clear verbal descriptions; they are dealt with in the mind by a visual, nonverbal process. Pyramids, cathedrals, and rockets exist not because of geometry or thermo-dynamics (动力学), but because they were first the picture in the minds of those who built them.
The creative shaping process of a technologist's mind can be seen in nearly every artifact (人工制品 that exists. For example, in designing a diesel engine, a technologist might express individual (个人的) ways of nonverbal thinking on the machine by continually using an intuitive (直觉的) sense of rightness and fitness. What would be the shape of the combustion chamber (燃烧室)？ Where should the valves (阀) be placed？ Such questions have a range of answers that are supplied by experience, by physical requirement, by limitations of available space, and not in the least by a sense of form. Some decisions, such as wall thickness and pin diameter, may depend on scientific calculations, but the nonscientific component design remains primary.
Design courses, then, should be an essential element of engineering curricula. Nonverbal thinking, a central mechanism in engineering design, involves perceptions, which is the special technique of the artist, not the scientist. Because perceptive processes are not assumed to need "hard thinking", nonverbal thought is sometimes seen as a primitive stage in the development of cognitive processes and inferior to verbal mathematical thought.
If courses in design, which in a strongly analytical (分析的) engineering curriculum provide the background required for practical problem-solving, are not provided, we can expect to encounter silly but costly errors occurring in advanced engineering systems. For example, early modes of high-speed railroad cars loaded with high-tech controls were unable to operate in a snowstorm because the fan sucked snow into the electrical system. Random failures that bring automatic control systems into trouble are a reflection of the chaos that results when design is assumed to be primarily a problem in mathematics.
The passage is mainly concerned with
Mother Nature Shows Her Strength
Tornadoes (龙卷风) and heavy thunderstorms moved across the Great Lakes and into Trumbull County on Saturday evening. The storms were dramatic and dangerous.
George Snyder was driving the fire truck down Route 88 when he first noticed that a funnel (漏半状的)cloud was behind him. "I stopped the truck and watched the funnel cloud. It was about 100 feet off the ground and I saw it go up and down for a while. It was moving toward Bradley Road and then suddenly it disappeared," Snyder said.
Snyder only saw one of the funnel clouds that passed through northeastern Ohio on Saturday. In Trumbull County, a tornado turned trees onto their sides. Some trees felt onto houses and cars. Other trees fell into telephone and electrical wires as they went down.
Amanda Symcheck was having a party when the storm began. "I knew something was wrong," she said. "I saw the sky go green and pink (粉红色). Then it sounded like a train rushing toward the house. I started crying and told everyone to go to the basement for protection."
The tornado caused a lot of damage to cars and houses in the area. It will take a long time and much money to repair everything. There was also serious water damage from the thunderstorms. The heavy rains and high wind caused the power to go out in many homes.
The storms caused serious flooding in areas near the river. More than four inches of rain fell in parts of Trumbull County. The river was so high that the water ran into streets and houses. Many streets had to be closed to cars and trucks because of the high water. This made it difficult for fire trucks, police cars, and other rescue vehicles to help people who were in trouble.
Many people who live near the river had. to leave their homes for their own safety. Some people reported five feet of water in their homes. Local and state officials opened emergency shelters for the people who were evacuated (撤走). The Red Cross served meals to them.
"This was a really intense storm," said Snyder. "People were afraid. Mother Nature can be fierce. We were lucky this time. No one was killed."
The weather was nice in Trumbull County on Saturday evening.
A Thirsty World
The world is not only hungry, it is also thirsty for water. This may seem strange to you, since nearly 75% of tile earth's surface is covered with water. But about 97% of this huge amount is sea-water, or salt water. Man can only drink and use the other 3%-the fresh water that comes from rivers, lakes, underground, and other sources. And we cannot even use all of that, because some of it Is in the form. of icebergs (冰山) and glaciers (冰川). Even worse, some of it has been polluted.
At the moment, this small amount of fresh water is still enough for us. However, our need for water is increasing rapidly. Only if we take steps to deal with this problem now can we avoid a severe worldwide water shortage later on. A limited water supply would have a bad effect on agriculture and industry.
In addition to stopping wasting our precious water, one useful step we should take is to develop ways of reusing it, Experiments have already been done in this field, but only on a small scale.
Today, in most large cities, water is used only once and it eventually returns to the sea or runs into underground storage tanks. But it is possible to pipe water that has been used to a purifying (净化) plant. There it can be filtered (过滤) and treated with chemicals so that it can be used again just as if it were fresh from a spring.
But even if every large city purified and reused its water, we still would not have enough. Where could we turn next？ To the oceans! All we'd have to do to make use of the vast amount of sea-water is-remove the salt. This salt-removing process is already in use in many parts of the world.
So if we take all these steps, we'll be in no danger of drying up!
The phrase "the world" in the first line of the passage refers to
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