Sugar is so much a part of our modern life that we only really think about it when, for some 11 , we cannot obtain it. It has been known to man for at least 3,000 years, but has 12 into common use only in 13 times. Until quite recently it was considered as a medicine and as a luxury for the very rich only.
Sugar is, then, 14 to our civilization. But what 15 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 and the sugar beet . But there are in fact many types of sugar, and the chemist recognizes hundreds of different 16 , each coming from a different source.
About 90% of the sugar is produced as food. Only 10% is used in industry for 17 other than food production. Yet sugar has great possibilities for use as the basis of chemicals. It can even be used for making plastics. In the future these potential uses will certainly be developed more than in the past.
There are many reasons why we should 18 the production of sugar. Most important is that it is one of the most highly concentrated of energy foods.
Thus sugar cane and beet produce an average of 7,000,000 calories per acre. In this way they have the advantage over potatoes which give only 4, 000, 000, while the 19 for wheat and beans is 2 ,000,000 each. So three acres of land growing wheat, beans and potatoes give only 20 more energy than one acre
of sugar.
A. slightly B. intention C. reason D. modern
E. strongly F. figure G. come H. significant
I. exactly J. increase K. proposals L. turn
M. purposes N. varieties O. serious
II. C 12. G 13. D 14. H 15. I 16. N 17. M 18. J 19. F 20. A
雅思听力复习资料推荐
雅思听力不能忽视前后搭配及语法
雅思听力的模仿原则和量的把握
雅思听力七大陷阱的破解指南
雅思听力高分备考方法:眼观六路耳听八方
详解雅思听力地图题
雅思听力中的顺序原则和重复原则
雅思听力考试形式题型解析
详解雅思听力地图题型
雅思听力新生入学场景高频词汇
雅思听力不能忽视字数限制问题
如何突破雅思听力观点题
雅思听力提高需打好词汇和语法基础
雅思听力水平提高方法:听抄训练
详解雅思听力备考中的三大误区
雅思听力必知的13个原则
雅思听力填空题全方位指导
雅思听力不能忽视名词复数形式
雅思听力中国外文化背景知识比例大
雅思听力餐饮场景热词整理
雅思听力必备场景整理
雅思听力考试的十三条潜规则
如何听懂雅思听力里的连读
详解雅思听力考试中的单选题
雅思听力提升方法介绍
雅思听力考场需要注意的六点
雅思听力词汇听不懂易成障碍
雅思听力选择题解题方法指导
如何突破雅思听力7分瓶颈
雅思听力不能忽视拼写及缩写
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |