Forthousandsofyears,peoplethoughtofglassassomethingbeau...

问题详情：

For thousands of years, people thought of glass as something beautiful to look at. Only recently have they come to think of it as something to look through. Stores display their goods in large glass windows. Glass bottles and jars that hold food and drink allow us to see the contents. Glass is used to make eyeglasses, microscopes, telescopes, and many other extremely useful and necessary objects.

    Until the Second World War, most of the glass used for optical instruments was imported from Europe. However, during the war Americans could not get European glass, and they were forced to make their own. As a result, new kinds of glasses were developed that had been previously unknown. These new effects were achieved by mixing other chemical elements with the sand. Some of these new glasses are very strong and can resist many kinds of shocks. Legend has it that a very hard glass was invented by a Roman who showed his discovery to the Emperor. When the Emperor saw the glass he feared that it would become more valuable than gold and sliver, making his treasure worthless. Therefore, he had the glassmaker killed, and the secret was not discovered again for hundreds of years.

In the present century, safety glass was invented for use in modern cars and planes. Safety glass is made by placing a layer of plastic between two layers of plate glass. When the outside layer of glass is broken, the pieces do not scatter and injure people. Some glass of the type is strong enough to resist bullets.

Although in recent years plastics have replaced glass under conditions where glass might be easily broken, there are new uses being developed , for the greatest advantage of glass is that its component parts are inexpensive and can be found all over the world.

29. With the passage of time, glass _________.

   A. is regarded as transparent

   B. is no longer seen as decoration

   C. is used to make things look pleasant

   D. is widely used to replace steel in making containers

30. Why did Americans make their own glass during the Second World War?

   A. The war blocked the way of glass import.

   B. They refused to use the European glass.

   C. The glass made in Europe was out of date.

   D. They were able to make a new kind of glass.

31. By telling the legend, the author wants to _________.

   A. prove that the Roman was the first inventor of hard glass

   B. support that the Americans were as clever as the Romans

   C. give some interesting information about hard glass

   D. provide a historical event concerned with hard glass

uses of glass are being developed on the ground that _________.

   A. glass is not as safe as plastics 

   B. glass is not as strong and durable as plastics

   C. glass is easily obtainable and inexpensive

   D. glass is more and more widely used

【回答】

BACC

知识点：阅读理解

题型：阅读理解