Although man has known asbestos for many hundreds of years, it was not until 160

Although man has known asbestos （石棉） for many hundreds of years, it was not until 160years 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 responsiblefor the opening of that first mine．

Mr.Johns was given a piece of asbestos which had beenfound in Italy． He experimented with the material and thenshowed its surprising powers to his customers. After putting on a pair ofasbestos gloves, which looked much like ordinary work gloves, he took red-hotcoals from the fireplace and played with them in his hands.How astonished thecustomers were to discover that he was not burned at all．You can well imagine that he had increasing businessin asbestos roofing materials． However, because it wasvery expensive to transport them from Italy to the United States, Mr.Johns sentout a young scientist to seek a source nearer home. This young man found greatvein（岩脉）, in the province of Quebec in Canada．

Ever since 1881 Quebec has led the world in theproduction 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 isseparated, a strange thing happens: the rock breaks down into fine, soft, soapyfibres．

Scientists do not know why the rock can be separatedeasily into threads, but they have found thousands of uses of this fireproofmaterial, of the so-called “cloth of stone”．

1.Which title best expresses the main idea of thispassage?

A．Asbestosmined in Canada                 B．Fireproofmatter

C．A “wonder” mineral                  D．A new roofingmaterial

2.Johns proved his ability as a salesman by_______．

A．going intoroofing business                B．carryingasbestos from Italy

C．sending atrained scientist                 D．showing theuse of asbestos gloves

3.Which is the most important characteristic ofasbestos that the author wants to show us?

A．It is likethread．                       B．It feelssoapy．

C．It burns easily．                        D．It isunusually heavy．

4.The author’s main purpose in writing this passagewas to _______．

A．show the needfor more scientists

B．compareasbestos with other minerals

C．increase thesales of asbestos

D．present factsabout asbestos

试题答案

【答案】

1.C

2.D

3.A

4.D

【解析】

试题