When aluminum was first produced about a hundred and fifty years ago, it was so difficult to separate form the ores in which it was found that its price was higher than that of gold. The price remained high until a new process was discovered for refining the metal with the aid of electricity approximately three quarters of a century later. The new method was so much cheaper that aluminum because practical for many purposes, one of which was making pots and pans.

　　Aluminum is lightweight, rustproof and easily shaped into different forms. By mixing it with other metals, scientists have been able to produce a variety of alloys, some of which have the strength of steel but weigh only one third as much.

　　Today, the uses of aluminum are innumerable. Perhaps its most important use is in transportation. Aluminum is found in the engine of automobiles, in the hulls of boats. It is also used in many parts of airplanes. In fact, the huge “airbus” planes would probably never have been produced if aluminum did not exist. By making vehicles lighter in weight aluminum has greatly reduced the amount of fuel needed to move them, Aluminum is also being used extensively in the building industry in some countries.

　　Since aluminum is such a versatile (多用的) metal, it is fortunate that bauxite (鋁土礦), which is one of its chief sources, is also one of the earth’s most plentiful substances. As the source of aluminum is almost inexhaustible, we can expect that more and more uses will be found for this versatile metal.

　　6. The price of aluminum was sharply reduced when people discovered a new refining process with the aid of .

　　A. wind B. solar energy C. hydraulic power D. electricity

　　7. Aluminum is .

　　A. lightweight, rustproof but not easily shaped into different forms

　　B. heavyweight, rustproof and easily shaped into different forms

　　C. lightweight, rustproof and easily shaped into different forms

　　D. lightweight and easily shaped into different forms but it is easy to become rusty

　　8. Which of the following is NOT true?

　　A. Aluminum is widely used in transportation.

　　B. Aluminum is also used in many parts of airplanes.

　　C. Aluminum is being used extensively in the building industry.

　　D. Aluminum is not used in its pure form.

　　9. Aluminum is found on earth mostly in the form of .

　　A. pure metal B. bauxite C. gold D. liquid

　　10. What is the passage talking about?

　　A. The features of aluminum and its functions. B. The process of aluminum.

　　C. The discovery of aluminum. D. The promising future of aluminum.

　　【答案】6-10 DCDBA