大学英语四级英译汉练习九

　　练习九
　　Directions: Read the underlined sentences carefully, and then translate them into Chinese. You may check your answers after you finish them.
　　Passage One
　　Rockets come into all sizes. Any rocket is interesting and often exciting, but there is one that also promises to be wonderful fun for the pilot. This rocket is designed to carry one person through the air for short distances.
　　Imagine a person able to rise higher than the treetops, to soar like a wingless bird over hills, streams, or even buildings. Then, just by turning a handle, he or she can settle gently to earth again. All this is possible with a fascinating invention, hardly larger than a life jacket, called a rocket belt.
　　The rocket belt looks like a padded vest（护垫背心）with two steel tanks on the back and a handgrip（柄）extending over each shoulder. Turning the left handgrip lets the pilot rifse into the air, higher than the tops of trees. Turning the right handgrip lets him or her speed ahead, like a wingless bird. By controlling the right grip and body motions, the pilot can come to a stop in the air. Then, by regulating the thrust with the left hand, the pilot can come back to earth gently.
　　A rocket engine may be thought of as a special kind of furnace in which fuels are burned very rapidly at very high temperatures. The burning fuel creates hot gases. The hot gases then expand and push against the inside of the engine.
　　Imagine a steel cylinder（汽缸，泵筒体）with no openings except two tiny ones where fuel and oxygen enter.The fuel burns and gas is formed. This gas expands, pushing equally in all directions. Pressure becomes so great that, unless it is relieved, the cylinder will burst.
　　But before the steel cylinder can burst, the end opposite the fuel intake is suddenly opened and the hot gases rush out. More gases are formed instantly as the fuel continues to burn. The gases push against all parts of the cylinder except for the open end. This causes the cylinder to move away from the open end where there is no pressure.
　　Passage Two
　　As supplier of most of the food we eat and of raw material for many industrial processes, agriculture is clearly an important area of the economy. But the industrial performance of agriculture is even more important than this. For in nations where the productivity of farmers is low, most of the working population is needed to raise food and few people are available for production of investment goods or for other activities required for economic growth. Indeed, one of the factors related most closely to the per capita income （人均收入）of a nation is the fraction（一部分）of its population engaged in farming. In the poorest nations of the world, more than half of the population llives on farms. This compares sharply with less than 10% in western Europe and less than 4% in the United States.
　　In short, the course of economic development in general depends in a fundamental way on the performance of farmers. This performance, in turn, depends on how agriculture is organized and on the economic environment, or market structure, within which it functions. In the following pages the performance of American agriculture is examined. It is appropriate to begin with a consideration of its market structure.
　　Passage Three
　　Another thing to remember in connection with concrete is that you are not allowed very much leeway（余地）for errors in either measurements or location. Once you have a solid mass of concrete set in place, it is going to stay there. You have a difficult job ahead of you if you try to remedy a mistake. Make very sure, before you fill the form, that everything is where and how you want it.
　　There are numerous rules regarding the proper mixing, handling, and finishing of concrete, but the essential one concerns the amount of water to use. The less water in the mix, the less the finished job will shrink. The less water used, the harder and more enduring the job after it has set.
　　The amateur concrete worker is annoyed with two desires. One is to use enough water to have the concrete nice and soft and easy to push around. You have been warned against that. The second is to take off the wooden forms too early, to see what the job looks like. That is really fatal. If the forms are stripped off too soon, while the concrete is still “green”, two things are likely to cause a major crack or defect in the body of the work. An excellent rule is to wait until you are sure the concrete is properly hardened, and then wait another day before removing the forms.
　　Passage Four
　　For years children in the industrial areas of Europe and America seldom left their smoky cities to see the beauties of the countryside. Not that the woods and fields were always far away, but they were too far from the city to permit people to make a round trip between morning and nightfall. What’s more, factory workers did not have enough money to send their children on country holidays away from home.
　　In 1907 a young German schoolmaster had an idea which changed this state of affairs. He decided to turn his little schoolhouse into a dormitory for the summer holidays. Anyone who brought his sleeping bag and cooking equipment along could stay there for a very small amount of money. The idea was a success. A few years later the schoolhouse was far too small to hold so many young people who wanted to stay there. So, a dormitory was set up in an old castle nearby. This was the first Youth Hostel.
　　Today young students and workers of every country can meet in the hostels and get to know each other. Some spend a week or more in the same hostel, seeing the surrounding sights and meeting the people of the area. Other youths go on foot or by bicycle from place to place, spending a night or two in one hostel, then going to the next.
　　Sometimes an informal program will be organized after the meal, with dances, songs, or short talks about other places, just by meeting people who come from places. Hence a few weeks spent “hostelling” can be just as useful a part of one’s education as classes in school.