12 月英语四六级考试阅读提高练习(38)Sugar is, then, ___4 ___to our civilization
But what___5___ 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 under ground)
But there are in fact many types of sugar, and the chemist recognizes hundreds of different ___6___ , each coming from a different source
About 90% of the sugar is produced as food
Only 10% is used in industry for ___7___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