The additive used in the first polymer nanocomposite reported by Toyota is ____.

An additive used to improve the ability of a lube oil to reduce friction is known as a/an

A.suppressant additive

B.dispersant additive

C.extreme pressure additive

D.viscosity improver additive

Which lubricating oil additive is used in diesel engines to reduce the tendency(倾向)for sludge and varnish to form on the engine parts？

A.Flash point improvers

B.Pour point improvers

C.Inhibitors

D.Foam suppressors(抑制物)

Passage Three

In an age when waste today means a lack tomorrow, making use of every available resource becomes more and more important. As coal is being used in greater and greater amounts to produce electricity, larger amounts of ash, by-product of coal, are produced. When coal is burned

in a boiler, two kinds of ash by-product are produced, a heavy bottom ash and a fine-as-powder fly ash that is filtered and captured by precipitators. About 10 to 15 percent of the coal by-product is bottom ash which is used like sand on icy city streets and highways and also on highways as paving material. It is the fly ash, however, that is receiving the greater amount of attention. Fly ash may be used as an additive to concrete in the construction of dams, bricks, and roads, and can replace up to 20 percent of the cement used in concrete. As a by-product of burned coal, fly ash requires no additional expenditure of energy to be produced, while cement production requires great amounts of energy.

In addition to using fly ash as a concrete additive, the technology is available to extract the main mineral components-aluminum, silicon, and magnetic. Today, extracting these components is a very expensive process, but the time may come when it is cheaper to extract these products from ash than to mine new supplies.

41. What can be used as a material to pave roads？

A. The coal by-product.

B. Additive.

C. Fine-as-powder fly ash.

D. Both B and C.

最大增溶浓度(maximum additive concentration，MAC)

A.additive

B.none

C.no-export

D.no-advertise

E.local-as

()是食品添加剂的意思。

A.Fresh flour

B.Food powder

C.Fresh cream

D.Food additive

the need to change their eating habits, because much of the food they eat, particularly foods, is not good for the health. Consequently, there has been a growing interest in natural foods: foods which do not contain chemical additives and which have not been affected by chemical fertilizers, widely used in farming to- day.

Natural foods, for example, vegetables, fruits and grains which have been grown in soil that is rich in organic matter. In simple terms, this means that the soil has been nourished by unused vegetable matter, which provides it with essential vitamins and minerals. This in itself is a natural process compared with the use of chemicals and fertilizers, the main purpose of which is to increase the amount—but not the quality—of foods grown in commercial farming areas.

Natural foods also include animals which have been allowed to feed and move freely in healthy pastures. Compare this with what happens in the mass production of poultry: there are battery farms, for ex- ample, where thousands of chickens live crowded together in one building and are fed on food which is little better than rubbish. Chickens kept in this way are not only tasteless as food; they also produce eggs which lack important vitamins.

There are other aspects of healthy eating which are now receiving increasing attention from experts on diet. Take, for example, the question of sugar, this is actually a non-essential food! Although a natural alternative, such as honey, can be used to sweeten food if this is necessary, we can in fact do without it. It is not that sugar is harmful in itself. But it does seem to be an additive: the quantity we use has grown steadily over the last two centuries and in Britain today each person consumes an average of 200 pounds a year! Yet all it does is provide us with energy, in the form. of calories. There are no vitamins in it, no minerals and no fibre.

It is significant that nowadays fibre is considered to be an important part of a healthy diet. In white bread, for example, the fibre has been removed. But it is present in unrefined flour and of course in vegetable. It is interesting to note that in countries where the national diet contains large quantities of unrefined flour and vegetable, certain diseases are comparatively rare. Hence the emphasis placed on the eating of wholemeal bread and more vegetables by modern experts on healthy eating.

Recently, some people are interested in natural foods because ______.

A．these foods are fresh and sweet

B．they want to change their eating habits

C．these foods do not contain chemical additives and have not been affected by chemical fertilizers

D．they don't like the processed foods

A.Additive（相加）

B.Subtractive（相减）

C.Filter（过滤器）

D.AdvancedTransparency（高级透明）