Although man has known asbestos for many hundreds of years， it was not until 160 years ago that it was mined for the first time on the North American continent. H. W. Johns， owner of a New York City Supply Shop for roofers， was responsible for the opening of that first mine. Mr. Johns was given a piece of asbestos which had been found in Italy. He experimented with the material and then showed its surprising powers to his customers. After putting on a pair of asbestos gloves， which looked much like ordinary work gloves， he took red-hot coals from the fireplace and played with them in his hands. How astonished the customers were to discover that he was not burned at all. You can well imagine that he had increasing business in asbestos roofing materials. However， because it was very expensive to transport them from Italy to the United States， Mr. Johns sent out a young scientist to seek a source nearer home. This young man found great vein， in the province of Quebec in Canada. Ever since 1881 Quebec has led the world in the production of this unusual mineral， which is made up of magnesium， silicon， iron， and oxygen. When it is mined， the asbestos is heavy， just as you would expect a mineral to be. When it is separated， a strange thing happens； the rock breaks down into fine， soft， soapy fibres。

    Scientists do not know why the rock can be separated easily into threads， but they have found thousands of uses of this fireproof material， of the so-called "cloth of stone".

    1. Which title best expresses the main idea of this passage？

    A. Asbestos mined in Canada

    B. Fireproof matter

    C.A "wonder" mineral

    D. A new roofing material

    2. Johns proved his ability as a salesman by_______.

    A. going into roofing business

    B. carrying asbestos from Italy

    C. sending a trained scientist

    D. showing the use of asbestos gloves

    3. Which is the most important character of asbestos that the author wants to show us？

    A. It is like thread.

    B. It feels soapy.

    C. It burns easily.

    D. It is unusually heavy.

    4. The author's main purpose in writing this passage was to _______.

    A. show the need for more scientists

    B. compare asbestos with other minerals

    C. increase the sales of asbestos

    D. present facts about asbestos

「答案解析」

本文讲述了耐火材料石棉在北美的开采过程及它的神奇耐火作用。

    1. C.主旨题。短文主要介绍了石棉的神奇作用。故C最佳。

    2. D.细节题。根据 After putting on a pair of asbestos gloves， …took red-hot coals from the fireplace and played with them in his hands 可推知，他是用当场演示的方法来推销他的产品的。故答案为D.

    3. A.推断题。根据When it is separated， a strange thing happens； the rock breaks down into fine， soft， soapy fibres 及 Scientists do not know why the rock can be separated easily into thread 可以断定答案为A.

   4. D.推断题。从短文中可以看出来作者写这篇文章只不过陈述事实而已。