[单项选择] Sugar is so much a part of our modern life that we only really think about it when, for some reason, we cannot obtain it. It has been known to man for at least 3,000 years, but has come into common use only in modern times. Until quite recently it was considered as a medicine and as a luxury for the very rich only. Sugar is, then, very important to our civilization. But what exactly is it Of course, most of us recognize sugar immediately as the sweet material which we put in coffee or cakes. This common form of sugar is derived from two plants: the sugar cane (a type of grass which grows to a height of twenty feet) and the sugar beet (which grows underground). But there are in fact many types of sugar, and the chemist recognizes hundreds of different varieties, each coming from a different source. About 90% of the sugar produced as food. Only 10% is used in industry for purposes other than food production. Yet sugar has great possibilities for use as the basis of chemica
A. What sugar is
B. Sugar Through the Ages
C. The Advantages of Sugar
D. Present and Future Uses of Sugar

[单项选择] Sugar is so much a part of our modern life that we only really think about it when, for some reason, we cannot obtain it. It has been known to man for at least 3,000 years, but has come into common use only in modern times. Until quite recently it was considered as a medicine and as a luxury for the very rich only. Sugar is, then, very important to our civilization. But what exactly is it Of course, most of us recognize sugar immediately as the sweet material which we put in coffee or cakes. This common form of sugar is derived from two plants: the sugar cane (a type of grass which grows to a height of twenty feet) and the sugar beet (which grows underground). But there are in fact many types of sugar, and the chemist recognizes hundreds of different varieties, each coming from a different source. About 90% of the sugar produced as food. Only 10% is used in industry for purposes other than food production. Yet sugar has great possibilities for use as the basis of chemica
A. about 90% of sugar used as food
B. only 10% used in industry
C. sugar used for making plastics
D. future uses of sugar

[填空题]There (is) much in our life (which) we do not control (and we are) not even responsible (for).

• A. is
• B. which
• C. and we are
• D. for

[填空题]So we asked our friends to help us.
So we asked our friends ______ ______.

[填空题]Chemistry plays an important part in our life. The (1) ______ of a clock, (1) ______.
the clothes we wear, and our leather shoes are all made (2) ______. (2) ______.
the water we drink is chemically purified. The glass and (3) ______ of the mirror, (3) ______.
the manufacturing of light bulbs, the paint and plaster on our walls require chemistry. The cooking, digestion and
assimilation of the food are all chemical (4) ______ (4) ______.
The construction of an automobile may require many kinds of chemically made (5) ______ (5) ______.
Chemistry and its (6) ______ have helped us to live longer. (6) ______.
The science of medicine also (7) ______ heavily upon chemistry. (7) ______.
And with (8) ______ and

[单项选择]Electricity plays an essential part in our life. No one can deny that electric light is necessary for people’s life. However, can you imagine such a world where there is no (21) of electric light As darkness falls over, children read in the light given by oil lamps and candles. Youths (22) time only by talking instead of watching TV. Everything is surrounded by (23) shadows. (24) , we have a man named Edison. He created bulb that (25) for two days before burning out. He also developed successfully a system for (26) electricity from a central powerhouse. It is he that gives us electric light, gramophone, moving pictures--all those we take (27) granted.
After the invention of electricity, manufacturers increasingly applied the findings of invention to their businesses, (28) generating new industrial growth. Development of electricity leads to the (29) creations of new products and ma
A. faint
B. vague
C. dark
D. pale