Introduction to biology. Кулагина Ж.Д. - 13 стр.

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have no apparent blossoms. 3. Among animals there (be) a great variety of sizes, shapes
and colours. 4. There (be) a system of classification to keep track of this great number
of living things. 5. At the dawn of civilization there (be) only a few sciences. 6. There
(be) places where there (be) no pronounced seasonal variation in temperature. 7. There
(be) few localities where there (be) no animal life. 8. There (be) very few
bioluminescent animals in caves. 9. In nature there (be) rarely too much oxygen for
animal life. 10. There (be) forms that can reduce their oxygen requirements.

      Ex. 5. Put the verbs in brackets into a proper tense form.

1. No one (know) how many different kinds of plants and animal there are. 2. Some
scientists (estimate) the number of plants and animals as three million. 3. There (be)
some plants and animals that (pierce) our skin. 4. Some animals (feed) on the blood of
living things. 5. There (be) many other living things living and growing inside our
bodies. 6. By the present time we (learn) much about all the living around us. 7. A
system of classification (be set up).

      Ex. 6. In the sentences below change the Passive constructions into Active ones:

Model: Many secrets of life have been discovered by biologists.
       Biologists have discovered many secrets of life.

1. Many secrets of life have been discovered by biologists. 2. Up to the present time it
was named and described more than 840000 kinds of animals and 345000 kinds of
plants. 3. A system of classification has been set up. 4. Plants and animals are sorted
into groups according to their structure. 5. The only light in all this darkness is made by
animals themselves. 6. One more method of discovering the presence of that illness has
been found. 7. A lot of different kinds of plants and animals have been studied,
identified and named.

      Ex. 7. Change Active constructions into Passive ones.

Model: Some scientists estimate the number of plants and animals as three million.
       The number of plants and animals is estimated as three million.

1. Some scientists estimate the number of plants and animals as three million. 2. Many
of the plants provide us with food, clothing, shelter and medicines. 3. Some plants and
animals can pierce our skin. 4. Certain plants and animals may cause diseases. 5.
Scientists study living things with great care. 6. We have learned much about all the
living around us.

      Ex. 8. Translate the following sentences into Russian.