閲讀訓練：大學英語四級閲讀理解練習九

Directions: There are 4 passages in this part. 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 and mark the corresponding letter on the Answer Sheet with a single line through the centre.
　　Questions 1 to 5 are based on the following passage:
　　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（護墊背心）with two steel tanks on the back and a handgrip（柄）extending over each shoulder. Turning the left handgrip lets the pilot rise 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，泵筒躰）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.
　　1. This passage focuses on ________.
　　 A) rockets of all sizes
　　 B) the rocket belt
　　 C) rocket principles
　　 D) different rocket engines
　　2.The author has written the passage mainly for ________.
　　 A) young children
　　 B) experienced pilots
　　 C) scientists in the rocket field
　　 D) the common readers
　　3. What's the use of left handgrip in the rocket belt?
　　 A) It is used to control height, whether rising or landing.
　　 B) It is used to operate the engine.
　　 C) It is used to come to a stop in the air.
　　 D) It is used to fly a distance.
　　4.The author begins to discuss a rocket engine and a steel cylinder from the fourth paragraph on in order to _______.
　　 A) show that he is a specialist in this field
　　 B) prove that a rocket engine may be considered as a special kind of furnace
　　 C) make the readers understand how the rocket belt works
　　 D) tell the readers the functions of the engine and cylinder
　　5.In the following paragraph, which subject is the author probably going to talk in detail about ?
　　 A) how to train pilots
　　 B) how much a rocket belt cost
　　 C) where to buy a rocket belt
　　 D) functions of a rocket belt

　　Questions 6 to 10 are based on the following passage:　　
　　The concept of obtaining fresh water from icebergs that are pulled to populated areas and dry regions of the world was once treated as a joke more appropriate to cartoons than real life. But now it is being considered quite seriously by many nations, especially since scientists have warned that the human race will outgrow its fresh water supply faster than it runs out of food.
　　Glaciers（冰川，冰河）are a possible source of fresh water that have been overlooked until recently. Three-quarters of the Earth's fresh water supply is still tied up in glacial ice, a reservoir of undeveloped fresh water so immense that it could sustain all the rivers of the world for 1,000 years. Floating on the oceans every year are 7,659 trillion（兆）metric tons of ice wrapped in 10,000 icebergs that break away from the polar ice caps, more than ninety percent of them from Antarctica.
　　Huge glaciers that stretch over the shallow continental shelf give birth to icebergs throughout the year. Icebergs are not like sea ice, which is formed when the sea itself freezes; rather, they are formed entirely on land, breaking off when glaciers spread over the sea. As they drift away from the polar region, icebergs sometimes move mysteriously in a direction opposite to the wind, pulled by pieces of ice , icebergs have been known to drift as far north as 35 degrees south of the equator in the Atlantic Ocean. To surround them and steer them to parts of the world where they are needed would not be too difficult.
　　The difficulty arises in other technical matters, such as the prevention of rapid melting in warmer climates and the funneling（滙集）of fresh water to shore in great volume. But even if the icebergs lost half of their volume in pulling, the water they could provide would be far cheaper than that produced by removing salt from water.
　　6. According to the author, most of the world's fresh water is to be found in ________ .
　　 A) oceans
　　 B) rivers
　　 C) glaciers
　　 D) reservoirs
　　7. The word"it" in Line 3 refers to ___________ .
　　 A) an iceberg that is pulled
　　 B) obtaining fresh water from icebergs
　　 C) the population of dry areas
　　 D) real life
　　8. How are icebergs formed?
　　 A) They break off from glaciers.
　　 B) Seawater freezes.
　　 C) Rivers freeze.
　　 D) Small pieces of floating ice funneling.
　　9．With which of the following ideas would the author be likely to agree?
　　 A) Pulling icebergs to dry areas is economically possible.
　　 B) Removing salt from water. is the best way to obtain drinking water.
　　 C) Using water from icebergs is a very short- term solution to water shortage.
　　 D) Icebergs could not be pulled very far before they would melt.
　　10．It can be inferred from the passage that most icebergs _________ .
　　 A) become part of glaciers
　　 B) drift toward the polar region
　　 C) move in whichever direction the wind is blowing
　　 D) melt in the oceans