Class assignments. IX. Instead of the modal verbs use the equivalents in the proper tense:

IX. Instead of the modal verbs use the equivalents in the proper tense:

1. The doctor must determine the origin of the disease for its successful treatment. 2. The doctor could reveal the consolidation in the lung by the X-ray examination. 3. The scientist can observe a rapid growth of microorganisms under the microscope. 4. The doctor says that this patient may sit up.

X. Put the predicates into Past:

1. The infant must move as much as possible for the proper development of the body. 2. In this patient the proper functions of the heart can be impaired due to the grippe. 3. During work one must give rest to the organism (particularly to the brain and the eyes) every hour or half an hour. 4. His constant tiredness may impair his heart.

XI. Make the sentences negative and interrogative:

1. The researcher had to include various significant findings of his observations into the report. 2. At present the surgeon has to extend his investigations to make a proper conclusion. 3. We have to increase the amount of food given to this patient.

XII. Put general questions to the following sentences making other necessary changes:

1. Somebody wanted to speak to the doctor about the condition of patient Smirnov. 2. The boy has impaired something in his abdomen when he fell down.

3. Someone will have to describe the course of this patient's disease.

4. Everyone knows that phagocytes destroy microorganisms.

XIII. Translate into English:

1. Все знают, что микроорганизмы размножаются делением. 2. Долгое время Кох нигде не мог обнаружить бактерии холеры. 3. До Везалия никто не мог точно определить строение сердца человека. 4. Должен ли был ис­следователь доказать что-то новое этим опытом? 5. Всем известно, что температура тела бывает наиболее низкой утром и наиболее высокой в ран­ние вечерние часы.

XIV. Read the pairs of sentences and choose those corresponding to Text C:

1. a) Ivanovsky began to study various diseases of plants, b) Ivanovsky began to study the physiology of plants and microbiology. 2. a) Tobacco mosaic disease occurred due to viruses, b) Tobacco mosaic disease did not occur due to bacteria. 3. a) Ivanovsky had to pass the juice of the diseased plant through oxygenated fluid, b) Ivanovsky had to pass the juice of the diseased plant through a fine filter.

XV. Read and entitle Text D. Describe how bacteria invade the organism:

TextD

If there are no wounds on the skin no bacteria can invade it. But if any smallest wound exists then bacteria can pass into the tissue. The thin membranes about the eye, in the nose and throat have less protective properties against bacterial invasion and infection may often develop in these points.

The way by which a microorganism enters the human body is an important factor to determine the occurrence of any disease. Certain bacteria can persist and develop in the human body only coming into contact with the respiratory tract, others through contact with the mucus of the intestines.

The skin and mucus membranes of the body have a large number of bacteria, some of them are highly pathogenic in a favourable environment. The spread of these bacteria is controlled by the skin and phagocytes fighting against the invaders.

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