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B Choose the best variant to complete the sentences.
1. They can take the form of solids, liquids, sludges, or ( held, included, contained, comprised, kept under control) gases, and they are generated primarily by chemical production, manufacturing, and other industrial activities.
2. Unsuitable hazardous-waste storage or disposal frequently contaminates surface and (ground, pure, waste, drinking, clean) water supplies.
3. (Garbage, Refuse, Trash, Waste, Rubbish) is rubbish that includes bulky items such as old refrigerators, couches, or large tree stumps.
4. Household refuse should be stored in durable, easily cleaned containers with tight-fitting covers in order to minimize rodent or insect (infection, infestation, invasion, overrunning, diseases).
5. At shopping centres, hotels, or apartment buildings - where large quantities of refuse are generated – (trucks, plastic bags, galvanized containers, compactors, dumpsters) may be used for temporary storage until the waste is collected.
Вариант 10
1. Read the text and translate the extract in italic in written form.
IRRIGATION
Irrigation is the artificial application of water to soil to assist in the production of crops. Its most familiar form is the sprinkling of lawns in both arid and humid regions, and the contrast between the watered and unwatered lawns, even in a humid climate, illustrates its benefits. Wherever practiced, it is supplementary to the natural rainfall.
Scientific irrigation involves knowledge of the available water supply, its conservation and application to the land, the characteristics and needs of the different types of soil, and the requirements of the various crops to be produced.
In general, irrigation is most extensively practiced in arid regions where agriculture without it is precarious or impracticable, but it is also applied to lands of the semi-arid regions to increase the yield, and to special crops in humid regions, such as rice, sugar cane, lawns, garden flowers and vegetables.
In fact there are comparatively few regions so free from occasional drouth that irrigation would not be profitable if it could be cheaply provided.
The surface of the earth is composed of land and water, the latter being roughly three-fourths of the area and not habitable by man. Of the remaining one-fourth or land area, more than half is either too cold or too rocky for cultivation, and of the remainder the major portion is too arid for the production of crops, and only in part useful for grazing or other purposes. Even of the humid area, a very large part is in tropical Africa and South America, ill-adapted to civilization and development by means known at present.
Thus the area naturally available for cultivation is a very small proportion of the whole, but can in places be increased by artificially applying water to the soil where nature fails to do this.
An irrigated region has certain advantages over a humid region in the production of crops. There is much advantage in being able to apply the water at just the time and in just the quantity needed, and to withhold it at will. The soils of arid regions are apt to be better supplied with the mineral plant foods which have not been leached out by excessive rains, and the great promoter of life and growth, sunlight, is more intense and constant in an arid than in a humid region. If sufficient care and skill be applied to secure the full benefit of these important advantages, the acreage yields under irrigation may be made far larger than under natural precipitation.
The choice of a method of irrigation depends upon topography, soil conditions, crops to be grown, value of crop products, available water supply and other factors. Various types of irrigation techniques differ in how the water obtained from the source is distributed within the field. Sources of irrigation water can be groundwater extracted from springs or by using wells, surface water withdrawn from rivers, lakes or reservoirs or non-conventional sources like treated wastewater, desalinated water or drainage water.
Improper irrigation may waste large amounts of water and reduce crop yields. It frequently results in plant nutrients being leached from the soil. Excessive application of water causes high ground water level, waterlogging and salinity of soil. This may be corrected only by the construction of expensive drainage systems. Very often drainage works are constructed together with irrigation development to discharge both excess water and excess salts.
Improving irrigation would be much easier if we could see what is taking place below the soil surface, how rapidly the water moves downward, how far it penetrates into the soil, what happens when it reaches the hard soil layer, how and where the water is stored in the soil, how it is removed from the soil by plant roots and other soil conditions.
Grammar work