I. 1. In most cases the laser is like an optical knife which would be more accurate, less painful, and faster than scalpel.

II. 1. The discovery of laser opens up a completely new frequency territory to be explored.

III. 1. In the field of chemistry lasers are used either for diagnostics purposes or for producing chemical changes.

IV. 2. The discovery of the lasers opens up a completely new frequency territory to be explored. Besides its operating frequency other features of the laser make it a field were many scientists and engineers are working on ideas and applications that just could not be previously attempted. The thought of completely new applications, along with improvements in other applications, is what has generated the excitement over the lasers.

I. 1. About half of the water sources are polluted with industrial waste.

II. 1. It is necessary to find new alternative sources of energy.

III. 1. Waste disposal is a major problem in modern society.

IV. 1. I think underground nuclear weapon tests are a major threat to the environment.

V. 1. To avoid using non-biodegradable materials is the task of everyone.

VI. 1. Interrelations between man and the biosphere are of a fairly complex nature. Man, like every other living organism, depends for his life on what the biosphere provides: water, oxygen, food and shelter. On the other hand, the biosphere is strongly affected by all sorts of human activity.

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Примечаний нет.